diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d631159..aec50cb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,6 +34,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -107,6 +111,10 @@ jobs:
         java: [temurin@8]
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -211,13 +219,17 @@ jobs:
 
   dependency-submission:
     name: Submit Dependencies
-    if: github.event_name != 'pull_request'
+    if: github.event.repository.fork == false && github.event_name != 'pull_request'
     strategy:
       matrix:
         os: [ubuntu-latest]
         java: [temurin@8]
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -239,7 +251,7 @@ jobs:
       - name: Submit Dependencies
         uses: scalacenter/sbt-dependency-submission@v2
         with:
-          modules-ignore: rootjs_2.13 rootjs_3 docs_2.13 docs_3 rootjvm_2.13 rootjvm_3 rootnative_2.13 rootnative_3
+          modules-ignore: ff4s-open-feature-provider-flipt-it_2.13 ff4s-open-feature-provider-flipt-it_3 ff4s-open-feature-provider-flipt_native0.4_2.13 ff4s-open-feature-provider-flipt_native0.4_3 ff4s-open-feature-sdk_native0.4_2.13 ff4s-open-feature-sdk_native0.4_3 ff4s-open-feature-provider-flipt_2.13 ff4s-open-feature-provider-flipt_3 ff4s-open-feature-sdk_2.13 ff4s-open-feature-sdk_3 rootjs_2.13 rootjs_3 docs_2.13 docs_3 ff4s-open-feature-provider-flipt_sjs1_2.13 ff4s-open-feature-provider-flipt_sjs1_3 rootjvm_2.13 rootjvm_3 rootnative_2.13 rootnative_3 ff4s-open-feature-sdk_sjs1_2.13 ff4s-open-feature-sdk_sjs1_3
           configs-ignore: test scala-tool scala-doc-tool test-internal
 
   site:
@@ -250,6 +262,10 @@ jobs:
         java: [temurin@11]
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -286,7 +302,7 @@ jobs:
 
       - name: Publish site
         if: github.event_name != 'pull_request' && github.ref == 'refs/heads/main'
-        uses: peaceiris/actions-gh-pages@v3.9.3
+        uses: peaceiris/actions-gh-pages@v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: site/target/docs/site
diff --git a/.sbtopts b/.sbtopts
new file mode 100644
index 0000000..a17552d
--- /dev/null
+++ b/.sbtopts
@@ -0,0 +1,2 @@
+-J-Xmx4G
+-J-Xss2M
diff --git a/.scalafix-base.conf b/.scalafix-base.conf
deleted file mode 100644
index cce9476..0000000
--- a/.scalafix-base.conf
+++ /dev/null
@@ -1,35 +0,0 @@
-# run when explicitly called
-rules = [
-  DisableSyntax
-  NoAutoTupling
-  NoValInForComprehension
-  ProcedureSyntax
-  RedundantSyntax
-  OrganizeImports
-  RemoveUnused
-]
-
-# run on compile (not explicitly)
-# doesn't organize imports
-triggered.rules = [
-  DisableSyntax
-  NoAutoTupling
-  NoValInForComprehension
-  ProcedureSyntax
-  RedundantSyntax
-]
-
-# clashes with OrganizeImports
-RemoveUnused.imports = false
-
-OrganizeImports {
-  blankLines = Auto
-  groups = [
-    "re:javax?\\."
-    "re:scala\\."
-    "re:^(?!(io.cardell)).*$" # anything except mine
-    "*"
-  ]
-  expandRelative = true
-  removeUnused = true
-}
diff --git a/.scalafix.conf b/.scalafix.conf
index fb8030a..a9be9d2 100644
--- a/.scalafix.conf
+++ b/.scalafix.conf
@@ -5,8 +5,8 @@ rules = [
   NoValInForComprehension
 #  ProcedureSyntax
   RedundantSyntax
-#  OrganizeImports
-#  RemoveUnused
+  # OrganizeImports
+  # RemoveUnused
 ]
 
 # run on compile (not explicitly)
diff --git a/.scalafmt.conf b/.scalafmt.conf
index 450ce94..94e67d3 100644
--- a/.scalafmt.conf
+++ b/.scalafmt.conf
@@ -1,2 +1,4 @@
 version = 3.7.1
+include ".scalafmt-base.conf"
+
 runner.dialect = scala3
diff --git a/build.sbt b/build.sbt
index ca3e5af..3024fe6 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,10 +1,11 @@
 // https://typelevel.org/sbt-typelevel/faq.html#what-is-a-base-version-anyway
 ThisBuild / tlBaseVersion := "0.0" // your current series x.y
 
-ThisBuild / organization := "io.cardell"
+ThisBuild / organization     := "io.cardell"
 ThisBuild / organizationName := "Alex Cardell"
-ThisBuild / startYear := Some(2023)
-ThisBuild / licenses := Seq(License.Apache2)
+ThisBuild / startYear        := Some(2023)
+ThisBuild / licenses         := Seq(License.Apache2)
+
 ThisBuild / developers := List(
   // your GitHub handle and name
   tlGitHubDev("alexcardell", "Alex Cardell")
@@ -15,70 +16,128 @@ ThisBuild / tlSonatypeUseLegacyHost := false
 
 // publish website from this branch
 ThisBuild / tlSitePublishBranch := Some("main")
-ThisBuild / tlSiteKeepFiles := false
+ThisBuild / tlSiteKeepFiles     := false
 
 val Scala213 = "2.13.12"
-val Scala33 = "3.3.3"
+val Scala33  = "3.3.3"
 ThisBuild / crossScalaVersions := Seq(Scala213, Scala33)
-ThisBuild / scalaVersion := Scala213 // the default Scala
+ThisBuild / scalaVersion       := Scala213 // the default Scala
+
+// hack until integration tests can run in parallel
+// ThisBuild / Test / parallelExecution  := false
+Global / concurrentRestrictions += Tags.limit(Tags.Test, 1)
 
 lazy val projects = Seq(
   `flipt-sdk-server`,
-  `flipt-sdk-server-it`
+  `flipt-sdk-server-it`,
+  `open-feature-sdk`,
+  `open-feature-provider-flipt`,
+  `open-feature-provider-flipt-it`
 )
 
 lazy val commonDependencies = Seq(
   libraryDependencies ++= Seq(
-    "org.typelevel" %%% "cats-core" % "2.10.0",
-    "org.typelevel" %%% "cats-effect" % "3.5.3",
-    "org.scalameta" %%% "munit" % "1.0.0-RC1" % Test,
-    "org.typelevel" %%% "munit-cats-effect" % "2.0.0-M5" % Test
+    "org.typelevel" %%% "cats-core"         % "2.10.0",
+    "org.typelevel" %%% "cats-effect"       % "3.5.3",
+    "org.scalameta" %%% "munit"             % "1.0.0-RC1" % Test,
+    "org.typelevel" %%% "munit-cats-effect" % "2.0.0-M5"  % Test
   )
 )
 
 lazy val root = tlCrossRootProject.aggregate(projects: _*)
 
-lazy val `flipt-sdk-server` =
-  crossProject(JVMPlatform, JSPlatform, NativePlatform)
-    .crossType(CrossType.Full)
-    .in(file("flipt/sdk-server"))
-    .settings(commonDependencies)
-    .settings(
-      name := "ff4s-flipt-sdk-server",
-      libraryDependencies ++= Seq(
-        "org.http4s" %%% "http4s-client" % "0.23.26",
-        "org.http4s" %%% "http4s-ember-client" % "0.23.26",
-        "org.http4s" %%% "http4s-circe" % "0.23.26",
-        "io.circe" %%% "circe-core" % "0.14.7",
-        "io.circe" %%% "circe-parser" % "0.14.7",
-        "io.circe" %%% "circe-generic" % "0.14.7"
-      )
+lazy val `flipt-sdk-server` = crossProject(
+  JVMPlatform,
+  JSPlatform,
+  NativePlatform
+)
+  .crossType(CrossType.Full)
+  .in(file("flipt/sdk-server"))
+  .settings(commonDependencies)
+  .settings(
+    name := "ff4s-flipt-sdk-server",
+    libraryDependencies ++= Seq(
+      "org.http4s" %%% "http4s-client"       % "0.23.26",
+      "org.http4s" %%% "http4s-ember-client" % "0.23.26",
+      "org.http4s" %%% "http4s-circe"        % "0.23.26",
+      "io.circe"   %%% "circe-core"          % "0.14.7",
+      "io.circe"   %%% "circe-parser"        % "0.14.7",
+      "io.circe"   %%% "circe-generic"       % "0.14.7"
     )
+  )
 
-lazy val `flipt-sdk-server-it` =
-  crossProject(JVMPlatform)
-    .crossType(CrossType.Pure)
-    .in(file("flipt/sdk-server-it"))
-    .dependsOn(`flipt-sdk-server`)
-    .settings(commonDependencies)
-    .settings(
-      libraryDependencies ++= Seq(
-        "com.dimafeng" %% "testcontainers-scala-munit" % "0.41.3" % Test
-      )
+lazy val `flipt-sdk-server-it` = crossProject(JVMPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("flipt/sdk-server-it"))
+  .settings(commonDependencies)
+  .settings(
+    libraryDependencies ++= Seq(
+      "com.dimafeng" %% "testcontainers-scala-munit" % "0.41.3" % Test
     )
+  )
+  .dependsOn(`flipt-sdk-server`)
 
-lazy val docs =
-  project
-    .in(file("site"))
-    .enablePlugins(TypelevelSitePlugin)
-    .settings(
-      tlSiteHelium := {
-        import laika.helium.config.IconLink
-        import laika.helium.config.HeliumIcon
-        import laika.ast.Path.Root
-        tlSiteHelium.value.site.topNavigationBar(
-          homeLink = IconLink.internal(Root / "index.md", HeliumIcon.home)
-        )
-      }
+lazy val `open-feature-sdk` = crossProject(
+  JVMPlatform,
+  JSPlatform,
+  NativePlatform
+)
+  .crossType(CrossType.Pure)
+  .in(file("open-feature/sdk"))
+  .enablePlugins(NoPublishPlugin)
+  .settings(commonDependencies)
+  .settings(
+    name := "ff4s-open-feature-sdk",
+    libraryDependencies ++= Seq(
+      "io.circe" %%% "circe-generic" % "0.14.7"
     )
-    .dependsOn(`flipt-sdk-server`.jvm)
+  )
+
+lazy val `open-feature-provider-flipt` = crossProject(
+  JVMPlatform,
+  JSPlatform,
+  NativePlatform
+)
+  .crossType(CrossType.Pure)
+  .in(file("open-feature/provider-flipt"))
+  .enablePlugins(NoPublishPlugin)
+  .settings(commonDependencies)
+  .settings(
+    name := "ff4s-open-feature-provider-flipt"
+  )
+  .dependsOn(
+    `open-feature-sdk`,
+    `flipt-sdk-server`
+  )
+
+lazy val `open-feature-provider-flipt-it` = crossProject(JVMPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("open-feature/provider-flipt-it"))
+  .enablePlugins(NoPublishPlugin)
+  .settings(commonDependencies)
+  .settings(
+    name := "ff4s-open-feature-provider-flipt-it",
+    libraryDependencies ++= Seq(
+      "com.dimafeng" %% "testcontainers-scala-munit" % "0.41.3" % Test
+    )
+  )
+  .dependsOn(
+    `open-feature-provider-flipt`
+  )
+
+lazy val docs = project
+  .in(file("site"))
+  .enablePlugins(TypelevelSitePlugin)
+  .settings(
+    tlSiteHelium := {
+      import laika.helium.config.IconLink
+      import laika.helium.config.HeliumIcon
+      import laika.ast.Path.Root
+      tlSiteHelium.value.site.topNavigationBar(
+        homeLink = IconLink.internal(Root / "index.md", HeliumIcon.home)
+      )
+    }
+  )
+  .dependsOn(`flipt-sdk-server`.jvm)
+
+addCommandAlias("fix", "headerCreateAll;scalafixAll;scalafmtAll;scalafmtSbt")
diff --git a/flipt/sdk-server-it/src/test/scala/io/cardell/ff4s/flipt/FliptApiImplItTest.scala b/flipt/sdk-server-it/src/test/scala/io/cardell/ff4s/flipt/FliptApiImplItTest.scala
index 8d42c27..3829260 100644
--- a/flipt/sdk-server-it/src/test/scala/io/cardell/ff4s/flipt/FliptApiImplItTest.scala
+++ b/flipt/sdk-server-it/src/test/scala/io/cardell/ff4s/flipt/FliptApiImplItTest.scala
@@ -22,15 +22,15 @@ import com.dimafeng.testcontainers.ContainerDef
 import com.dimafeng.testcontainers.DockerComposeContainer
 import com.dimafeng.testcontainers.ExposedService
 import com.dimafeng.testcontainers.munit.TestContainerForAll
-import io.cardell.ff4s.flipt.auth.AuthenticationStrategy
 import io.circe.Decoder
 import io.circe.generic.semiauto.deriveDecoder
+import java.io.File
 import munit.CatsEffectSuite
 import org.http4s.Uri
 import org.http4s.ember.client.EmberClientBuilder
 import org.testcontainers.containers.wait.strategy.Wait
 
-import java.io.File
+import io.cardell.ff4s.flipt.auth.AuthenticationStrategy
 
 class FliptApiImplItTest extends CatsEffectSuite with TestContainerForAll {
 
@@ -43,10 +43,11 @@ class FliptApiImplItTest extends CatsEffectSuite with TestContainerForAll {
   )
 
   def api(containers: Containers): Resource[IO, FliptApi[IO]] = {
-    val flipt = containers
-      .asInstanceOf[DockerComposeContainer]
-      .getContainerByServiceName("flipt")
-      .get
+    val flipt =
+      containers
+        .asInstanceOf[DockerComposeContainer]
+        .getContainerByServiceName("flipt")
+        .get
 
     val url = Uri
       .fromString(
@@ -119,6 +120,7 @@ class FliptApiImplItTest extends CatsEffectSuite with TestContainerForAll {
   }
 
   case class TestVariant(field: String, intField: Int)
+
   object TestVariant {
     implicit val decoder: Decoder[TestVariant] = deriveDecoder
   }
@@ -166,4 +168,5 @@ class FliptApiImplItTest extends CatsEffectSuite with TestContainerForAll {
       }
     }
   }
+
 }
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApi.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApi.scala
index 8832b9b..58b72da 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApi.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApi.scala
@@ -17,6 +17,10 @@
 package io.cardell.ff4s.flipt
 
 import cats.effect.Concurrent
+import io.circe.Decoder
+import org.http4s.Uri
+import org.http4s.client.Client
+
 import io.cardell.ff4s.flipt.auth.AuthMiddleware
 import io.cardell.ff4s.flipt.auth.AuthenticationStrategy
 import io.cardell.ff4s.flipt.model.AttachmentDecodingError
@@ -25,14 +29,13 @@ import io.cardell.ff4s.flipt.model.BatchEvaluationResponse
 import io.cardell.ff4s.flipt.model.BooleanEvaluationResponse
 import io.cardell.ff4s.flipt.model.StructuredVariantEvaluationResponse
 import io.cardell.ff4s.flipt.model.VariantEvaluationResponse
-import io.circe.Decoder
-import org.http4s.Uri
-import org.http4s.client.Client
 
 trait FliptApi[F[_]] {
+
   def evaluateBoolean(
       request: EvaluationRequest
   ): F[BooleanEvaluationResponse]
+
   def evaluateVariant(
       request: EvaluationRequest
   ): F[VariantEvaluationResponse]
@@ -45,16 +48,19 @@ trait FliptApi[F[_]] {
   def evaluateStructuredVariant[A: Decoder](
       request: EvaluationRequest
   ): F[Either[AttachmentDecodingError, StructuredVariantEvaluationResponse[A]]]
+
   def evaluateBatch(
       request: BatchEvaluationRequest
   ): F[BatchEvaluationResponse]
+
 }
 
 object FliptApi {
+
   def apply[F[_]: Concurrent](
       client: Client[F],
       uri: Uri,
       strategy: AuthenticationStrategy
-  ): FliptApi[F] =
-    new FliptApiImpl[F](AuthMiddleware(client, strategy), uri)
+  ): FliptApi[F] = new FliptApiImpl[F](AuthMiddleware(client, strategy), uri)
+
 }
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApiImpl.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApiImpl.scala
index 7f6161c..1c1fbd9 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApiImpl.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/FliptApiImpl.scala
@@ -17,13 +17,7 @@
 package io.cardell.ff4s.flipt
 
 import cats.effect.Concurrent
-import cats.syntax.all.*
-import io.cardell.ff4s.flipt.model.AttachmentDecodingError
-import io.cardell.ff4s.flipt.model.BatchEvaluationRequest
-import io.cardell.ff4s.flipt.model.BatchEvaluationResponse
-import io.cardell.ff4s.flipt.model.BooleanEvaluationResponse
-import io.cardell.ff4s.flipt.model.StructuredVariantEvaluationResponse
-import io.cardell.ff4s.flipt.model.VariantEvaluationResponse
+import cats.syntax.all._
 import io.circe.Decoder
 import org.http4s.Method
 import org.http4s.Request
@@ -31,6 +25,13 @@ import org.http4s.Uri
 import org.http4s.circe.CirceEntityCodec._
 import org.http4s.client.Client
 
+import io.cardell.ff4s.flipt.model.AttachmentDecodingError
+import io.cardell.ff4s.flipt.model.BatchEvaluationRequest
+import io.cardell.ff4s.flipt.model.BatchEvaluationResponse
+import io.cardell.ff4s.flipt.model.BooleanEvaluationResponse
+import io.cardell.ff4s.flipt.model.StructuredVariantEvaluationResponse
+import io.cardell.ff4s.flipt.model.VariantEvaluationResponse
+
 protected[flipt] class FliptApiImpl[F[_]: Concurrent](
     client: Client[F],
     baseUri: Uri
@@ -64,9 +65,7 @@ protected[flipt] class FliptApiImpl[F[_]: Concurrent](
       request: EvaluationRequest
   ): F[
     Either[AttachmentDecodingError, StructuredVariantEvaluationResponse[A]]
-  ] = {
-    evaluateVariant(request).map(StructuredVariantEvaluationResponse[A](_))
-  }
+  ] = evaluateVariant(request).map(StructuredVariantEvaluationResponse[A](_))
 
   override def evaluateBatch(
       request: BatchEvaluationRequest
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthMiddleware.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthMiddleware.scala
index d8a7c68..aa2c11a 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthMiddleware.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthMiddleware.scala
@@ -16,14 +16,15 @@
 
 package io.cardell.ff4s.flipt.auth
 
-import org.http4s.headers.Authorization
 import cats.effect.kernel.MonadCancelThrow
-import org.typelevel.ci._
-import org.http4s.client.Client
-import org.http4s.Credentials
 import org.http4s.AuthScheme
+import org.http4s.Credentials
+import org.http4s.client.Client
+import org.http4s.headers.Authorization
+import org.typelevel.ci._
 
 object AuthMiddleware {
+
   def apply[F[_]: MonadCancelThrow](
       client: Client[F],
       strategy: AuthenticationStrategy
@@ -35,13 +36,15 @@ object AuthMiddleware {
   private def authHeader(
       strategy: AuthenticationStrategy
   ): Authorization = {
-    val credentials = strategy match {
-      case AuthenticationStrategy.ClientToken(token) =>
-        Credentials.Token(AuthScheme.Bearer, token)
-      case AuthenticationStrategy.JWT(token) =>
-        Credentials.Token(ci"JWT", token)
-    }
+    val credentials =
+      strategy match {
+        case AuthenticationStrategy.ClientToken(token) =>
+          Credentials.Token(AuthScheme.Bearer, token)
+        case AuthenticationStrategy.JWT(token) =>
+          Credentials.Token(ci"JWT", token)
+      }
 
     Authorization(credentials)
   }
+
 }
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthenticationStrategy.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthenticationStrategy.scala
index 9786cd3..555bbdb 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthenticationStrategy.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/auth/AuthenticationStrategy.scala
@@ -20,5 +20,5 @@ sealed trait AuthenticationStrategy
 
 object AuthenticationStrategy {
   case class ClientToken(token: String) extends AuthenticationStrategy
-  case class JWT(token: String) extends AuthenticationStrategy
+  case class JWT(token: String)         extends AuthenticationStrategy
 }
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/BatchEvaluationRequest.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/BatchEvaluationRequest.scala
index 1095e85..2ac0c7a 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/BatchEvaluationRequest.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/BatchEvaluationRequest.scala
@@ -16,9 +16,10 @@
 
 package io.cardell.ff4s.flipt.model
 
-import io.cardell.ff4s.flipt.EvaluationRequest
-import io.circe.generic.semiauto.deriveEncoder
 import io.circe.Encoder
+import io.circe.generic.semiauto.deriveEncoder
+
+import io.cardell.ff4s.flipt.EvaluationRequest
 
 case class BatchEvaluationRequest(
     requestId: Option[String],
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/ErrorEvaluationReason.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/ErrorEvaluationReason.scala
index 9771dff..ad16847 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/ErrorEvaluationReason.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/ErrorEvaluationReason.scala
@@ -24,7 +24,7 @@ sealed trait ErrorEvaluationReason
 
 object ErrorEvaluationReason {
   case object NotFound extends ErrorEvaluationReason
-  case object Unknown extends ErrorEvaluationReason
+  case object Unknown  extends ErrorEvaluationReason
 
   implicit val d: Decoder[ErrorEvaluationReason] = Decoder.instance { cursor =>
     val json = cursor.value
@@ -32,8 +32,7 @@ object ErrorEvaluationReason {
     json.asString match {
       case Some(v) if v == "NOT_FOUND_ERROR_EVALUATION_REASON" =>
         Right(NotFound)
-      case Some(v) if v == "UNKNOWN_ERROR_EVALUATION_REASON" =>
-        Right(Unknown)
+      case Some(v) if v == "UNKNOWN_ERROR_EVALUATION_REASON" => Right(Unknown)
       case Some(other) =>
         Left(
           DecodingFailure(
@@ -47,4 +46,5 @@ object ErrorEvaluationReason {
         )
     }
   }
+
 }
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationReason.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationReason.scala
index 9418503..12fa2d1 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationReason.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationReason.scala
@@ -23,23 +23,20 @@ import io.circe.DecodingFailure.Reason
 sealed trait EvaluationReason
 
 object EvaluationReason {
-  case object Unknown extends EvaluationReason
+  case object Unknown      extends EvaluationReason
   case object FlagDisabled extends EvaluationReason
-  case object Match extends EvaluationReason
-  case object Default extends EvaluationReason
+  case object Match        extends EvaluationReason
+  case object Default      extends EvaluationReason
 
   implicit val d: Decoder[EvaluationReason] = Decoder.instance { cursor =>
     val json = cursor.value
 
     json.asString match {
-      case Some(v) if v == "UNKNOWN_EVALUATION_REASON" =>
-        Right(Unknown)
+      case Some(v) if v == "UNKNOWN_EVALUATION_REASON" => Right(Unknown)
       case Some(v) if v == "FLAG_DISABLED_EVALUATION_REASON" =>
         Right(FlagDisabled)
-      case Some(v) if v == "MATCH_EVALUATION_REASON" =>
-        Right(Match)
-      case Some(v) if v == "DEFAULT_EVALUATION_REASON" =>
-        Right(Default)
+      case Some(v) if v == "MATCH_EVALUATION_REASON"   => Right(Match)
+      case Some(v) if v == "DEFAULT_EVALUATION_REASON" => Right(Default)
       case Some(other) =>
         Left(
           DecodingFailure(
@@ -53,4 +50,5 @@ object EvaluationReason {
         )
     }
   }
+
 }
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationRequest.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationRequest.scala
index 022dc4c..6c657d1 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationRequest.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationRequest.scala
@@ -16,8 +16,8 @@
 
 package io.cardell.ff4s.flipt
 
-import io.circe.generic.semiauto.deriveEncoder
 import io.circe.Encoder
+import io.circe.generic.semiauto.deriveEncoder
 
 case class EvaluationRequest(
     namespaceKey: String,
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationResponse.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationResponse.scala
index 99d9cab..8a8df98 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationResponse.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/EvaluationResponse.scala
@@ -23,12 +23,14 @@ import io.circe.generic.semiauto.deriveDecoder
 sealed trait EvaluationResponse
 
 object EvaluationResponse {
+
   implicit def decoder: Decoder[EvaluationResponse] =
     List[Decoder[EvaluationResponse]](
       Decoder[BooleanEvaluationResponse].widen,
       Decoder[VariantEvaluationResponse].widen,
       Decoder[ErrorEvaluationResponse].widen
     ).reduceLeft(_ or _)
+
 }
 
 case class BooleanEvaluationResponse(
diff --git a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/StructuredEvaluationResponse.scala b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/StructuredEvaluationResponse.scala
index 45feea0..a8c483c 100644
--- a/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/StructuredEvaluationResponse.scala
+++ b/flipt/sdk-server/shared/src/main/scala/io/cardell/ff4s/flipt/model/StructuredEvaluationResponse.scala
@@ -16,13 +16,14 @@
 
 package io.cardell.ff4s.flipt.model
 
-import cats.syntax.all.*
+import cats.syntax.all._
 import io.circe.Decoder
 import io.circe.parser
 
 sealed trait AttachmentDecodingError
+
 object AttachmentDecodingError {
-  case object AttachmentJsonParsingError extends AttachmentDecodingError
+  case object AttachmentJsonParsingError     extends AttachmentDecodingError
   case object AttachmentDeserialisationError extends AttachmentDecodingError
 }
 
@@ -38,14 +39,16 @@ case class StructuredVariantEvaluationResponse[A](
 )
 
 object StructuredVariantEvaluationResponse {
+
   def apply[A: Decoder](
       variant: VariantEvaluationResponse
   ): Either[AttachmentDecodingError, StructuredVariantEvaluationResponse[A]] = {
-    val maybeAttachment = if (variant.`match`) {
-      decodeJsonAttachment(variant.variantAttachment).map(Some(_))
-    } else {
-      Option.empty[A].asRight[AttachmentDecodingError]
-    }
+    val maybeAttachment =
+      if (variant.`match`) {
+        decodeJsonAttachment(variant.variantAttachment).map(Some(_))
+      } else {
+        Option.empty[A].asRight[AttachmentDecodingError]
+      }
 
     maybeAttachment.map { attachment =>
       StructuredVariantEvaluationResponse[A](
diff --git a/open-feature/provider-flipt-it/src/test/scala/io/cardell/openfeature/provider/flipt/FliptProviderItTest.scala b/open-feature/provider-flipt-it/src/test/scala/io/cardell/openfeature/provider/flipt/FliptProviderItTest.scala
new file mode 100644
index 0000000..392c0f8
--- /dev/null
+++ b/open-feature/provider-flipt-it/src/test/scala/io/cardell/openfeature/provider/flipt/FliptProviderItTest.scala
@@ -0,0 +1,186 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature.provider.flipt
+
+import cats.effect.IO
+import cats.effect.kernel.Resource
+import com.dimafeng.testcontainers.ContainerDef
+import com.dimafeng.testcontainers.DockerComposeContainer
+import com.dimafeng.testcontainers.ExposedService
+import com.dimafeng.testcontainers.munit.TestContainerForAll
+import java.io.File
+import munit.CatsEffectSuite
+import org.http4s.Uri
+import org.http4s.ember.client.EmberClientBuilder
+import org.testcontainers.containers.wait.strategy.Wait
+
+import io.cardell.ff4s.flipt.FliptApi
+import io.cardell.ff4s.flipt.auth.AuthenticationStrategy
+import io.cardell.openfeature.EvaluationContext
+
+class FliptProviderItTest extends CatsEffectSuite with TestContainerForAll {
+
+  override val containerDef: ContainerDef = DockerComposeContainer.Def(
+    new File("docker-compose.yaml"),
+    exposedServices = Seq(
+      ExposedService("flipt", 8080, Wait.forLogMessage("^UI: http.*", 1))
+    ),
+    tailChildContainers = true
+  )
+
+  def api(containers: Containers): Resource[IO, FliptProvider[IO]] = {
+    val flipt =
+      containers
+        .asInstanceOf[DockerComposeContainer]
+        .getContainerByServiceName("flipt")
+        .get
+
+    val url = Uri
+      .fromString(
+        s"http://${flipt.getHost()}:${flipt.getMappedPort(8080)}"
+      )
+      .getOrElse(throw new Exception("invalid url"))
+
+    EmberClientBuilder
+      .default[IO]
+      .build
+      .map { client =>
+        val flipt = FliptApi[IO](
+          client,
+          url,
+          AuthenticationStrategy.ClientToken("token")
+        )
+
+        new FliptProvider(flipt, "default")
+      }
+  }
+
+  test("can fetch boolean flag") {
+    withContainers { containers =>
+      api(containers).use { flipt =>
+        for {
+          res <- flipt.resolveBooleanValue(
+            "boolean-flag-1",
+            false,
+            EvaluationContext.empty
+          )
+        } yield assertEquals(res.value, true)
+      }
+    }
+  }
+
+  // test("uses default when boolean flag missing") {
+  //   withContainers { containers =>
+  //     api(containers).use { flipt =>
+  //       for {
+  //         res <- flipt.resolveBooleanValue(
+  //           "no-flag",
+  //           false,
+  //           EvaluationContext.empty
+  //         )
+  //       } yield assertEquals(res.value, false)
+  //     }
+  //   }
+  // }
+
+  // test("receives variant match when in segment rule") {
+  //   withContainers { containers =>
+  //     api(containers).use { flipt =>
+  //       val segmentContext = Map("test-property" -> "matched-property-value")
+  //       for {
+  //         res <- flipt.evaluateVariant(
+  //           EvaluationRequest(
+  //             "default",
+  //             "variant-flag-1",
+  //             None,
+  //             segmentContext,
+  //             None
+  //           )
+  //         )
+  //       } yield assertEquals(res.`match`, true)
+  //     }
+  //   }
+  // }
+  //
+  // test("receives no variant match when not in segment rule") {
+  //   withContainers { containers =>
+  //     api(containers).use { flipt =>
+  //       val segmentContext = Map("test-property" -> "unmatched-property-value")
+  //       for {
+  //         res <- flipt.evaluateVariant(
+  //           EvaluationRequest(
+  //             "default",
+  //             "variant-flag-1",
+  //             None,
+  //             segmentContext,
+  //             None
+  //           )
+  //         )
+  //       } yield assertEquals(res.`match`, false)
+  //     }
+  //   }
+  // }
+  //
+  // case class TestVariant(field: String, intField: Int)
+  // object TestVariant {
+  //   implicit val decoder: Decoder[TestVariant] = deriveDecoder
+  // }
+  //
+  // test("can deserialise variant match") {
+  //   withContainers { containers =>
+  //     api(containers).use { flipt =>
+  //       val segmentContext = Map("test-property" -> "matched-property-value")
+  //
+  //       for {
+  //         res <- flipt.evaluateStructuredVariant[TestVariant](
+  //           EvaluationRequest(
+  //             "default",
+  //             "variant-flag-1",
+  //             None,
+  //             segmentContext,
+  //             None
+  //           )
+  //         )
+  //         _ <- IO.println(res)
+  //         result = res.map(_.variantAttachment)
+  //       } yield assertEquals(result, Right(Some(TestVariant("string", 33))))
+  //     }
+  //   }
+  // }
+  //
+  // test("does not attempt variant deserialisation without a match") {
+  //   withContainers { containers =>
+  //     api(containers).use { flipt =>
+  //       val segmentContext = Map("test-property" -> "unmatched-property-value")
+  //
+  //       for {
+  //         res <- flipt.evaluateStructuredVariant[TestVariant](
+  //           EvaluationRequest(
+  //             "default",
+  //             "variant-flag-1",
+  //             None,
+  //             segmentContext,
+  //             None
+  //           )
+  //         )
+  //         _ <- IO.println(res)
+  //         result = res.map(_.variantAttachment)
+  //       } yield assertEquals(result, Right(None))
+  //     }
+  //   }
+  // }
+}
diff --git a/open-feature/provider-flipt/src/main/scala/io/cardell/openfeature/provider/flipt/FliptProvider.scala b/open-feature/provider-flipt/src/main/scala/io/cardell/openfeature/provider/flipt/FliptProvider.scala
new file mode 100644
index 0000000..4b53268
--- /dev/null
+++ b/open-feature/provider-flipt/src/main/scala/io/cardell/openfeature/provider/flipt/FliptProvider.scala
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature.provider.flipt
+
+import cats.MonadThrow
+import cats.syntax.all._
+
+import io.cardell.ff4s.flipt.EvaluationRequest
+import io.cardell.ff4s.flipt.FliptApi
+import io.cardell.ff4s.flipt.model.{EvaluationReason => FliptReason}
+import io.cardell.openfeature.ErrorCode
+import io.cardell.openfeature.EvaluationContext
+import io.cardell.openfeature.EvaluationReason
+import io.cardell.openfeature.provider.Provider
+import io.cardell.openfeature.provider.ProviderMetadata
+import io.cardell.openfeature.provider.ResolutionDetails
+
+class FliptProvider[F[_]: MonadThrow](flipt: FliptApi[F], namespace: String)
+    extends Provider[F] {
+
+  override def metadata: ProviderMetadata = ProviderMetadata(name = "flipt")
+
+  private def mapReason(evalReason: FliptReason): EvaluationReason =
+    evalReason match {
+      case FliptReason.Default      => EvaluationReason.Default
+      case FliptReason.FlagDisabled => EvaluationReason.Disabled
+      case FliptReason.Match        => EvaluationReason.TargetingMatch
+      case FliptReason.Unknown      => EvaluationReason.Unknown
+    }
+
+  private def mapContext(context: EvaluationContext): Map[String, String] =
+    context.values.map { case (k, v) => (k, v.stringValue) }
+
+  override def resolveBooleanValue(
+      flagKey: String,
+      defaultValue: Boolean,
+      context: EvaluationContext
+  ): F[ResolutionDetails[Boolean]] = {
+    val evalContext = mapContext(context)
+
+    val req: EvaluationRequest = EvaluationRequest(
+      namespaceKey = namespace,
+      flagKey = flagKey,
+      entityId = context.targetingKey,
+      context = evalContext,
+      reference = None
+    )
+
+    val resolution = flipt.evaluateBoolean(req).map { evaluation =>
+      ResolutionDetails[Boolean](
+        value = evaluation.enabled,
+        errorCode = None,
+        errorMessage = None,
+        reason = mapReason(evaluation.reason).some,
+        variant = None,
+        metadata = None
+      )
+    }
+
+    def default(t: Throwable) = ResolutionDetails[Boolean](
+      value = defaultValue,
+      errorCode = Some(ErrorCode.General),
+      errorMessage = Some(t.getMessage()),
+      reason = Some(EvaluationReason.Default),
+      variant = None,
+      metadata = None
+    )
+
+    resolution.attempt.map {
+      case Right(value) => value
+      case Left(error)  => default(error)
+    }
+  }
+
+  // override def resolveStringValue(
+  //     flagKey: String,
+  //     defaultValue: String,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[String]] = ???
+  //
+  // override def resolveIntValue(
+  //     flagKey: String,
+  //     defaultValue: Int,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[Int]] = ???
+  //
+  // override def resolveDoubleValue(
+  //     flagKey: String,
+  //     defaultValue: Double,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[Double]] = ???
+  //
+  // override def resolveStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     defaultValue: A,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[A]] = ???
+
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/ErrorCode.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/ErrorCode.scala
new file mode 100644
index 0000000..f9ac750
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/ErrorCode.scala
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+sealed trait ErrorCode
+
+object ErrorCode {
+
+  /** The value was resolved before the provider was initialized. */
+  case object ProviderNotReady extends ErrorCode
+
+  /** The flag could not be found. */
+  case object FlagNotFound extends ErrorCode
+
+  /** An error was encountered parsing data, such as a flag configuration. */
+  case object ParseError extends ErrorCode
+
+  /** The type of the flag value does not match the expected type. */
+  case object TypeMismatch extends ErrorCode
+
+  /** The provider requires a targeting key and one was not provided in the
+    * evaluation context.
+    */
+  case object TargetingKeyMissing extends ErrorCode
+
+  /** The evaluation context does not meet provider requirements. */
+  case object InvalidContext extends ErrorCode
+
+  /** The provider has entered an irrecoverable error state. */
+  case object ProviderFatal extends ErrorCode
+
+  /** The error was for a reason not enumerated above. */
+  case object General extends ErrorCode
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationContext.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationContext.scala
new file mode 100644
index 0000000..f865e11
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationContext.scala
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+import io.cardell.openfeature.ContextValue.BooleanValue
+import io.cardell.openfeature.ContextValue.DoubleValue
+import io.cardell.openfeature.ContextValue.IntValue
+import io.cardell.openfeature.ContextValue.StringValue
+
+sealed trait ContextValue {
+
+  def stringValue: String =
+    this match {
+      case StringValue(value)  => value
+      case BooleanValue(value) => value.toString()
+      case IntValue(value)     => value.toString()
+      case DoubleValue(value)  => value.toString()
+    }
+
+}
+
+object ContextValue {
+  case class BooleanValue(value: Boolean) extends ContextValue
+  case class StringValue(value: String)   extends ContextValue
+  case class IntValue(value: Int)         extends ContextValue
+  case class DoubleValue(value: Double)   extends ContextValue
+}
+
+case class EvaluationContext(
+    targetingKey: Option[String],
+    values: Map[String, ContextValue]
+) {
+
+  def ++(other: EvaluationContext): EvaluationContext = EvaluationContext(
+    other.targetingKey.orElse(targetingKey),
+    // TODO check override order in spec
+    values ++ other.values
+  )
+
+}
+
+object EvaluationContext {
+  def empty: EvaluationContext = EvaluationContext(None, Map.empty)
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationDetails.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationDetails.scala
new file mode 100644
index 0000000..bdf9431
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationDetails.scala
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+import io.cardell.openfeature.provider.FlagMetadata
+import io.cardell.openfeature.provider.ResolutionDetails
+
+case class EvaluationDetails[A](
+    flagKey: String,
+    value: A,
+    errorCode: Option[ErrorCode],
+    errorMessage: Option[String],
+    reason: Option[EvaluationReason],
+    variant: Option[String],
+    metadata: Option[FlagMetadata]
+)
+
+object EvaluationDetails {
+
+  def apply[A](
+      flagKey: String,
+      resolution: ResolutionDetails[A]
+  ): EvaluationDetails[A] = EvaluationDetails[A](
+    flagKey = flagKey,
+    value = resolution.value,
+    errorCode = resolution.errorCode,
+    errorMessage = resolution.errorMessage,
+    reason = resolution.reason,
+    variant = resolution.variant,
+    metadata = resolution.metadata
+  )
+
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationReason.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationReason.scala
new file mode 100644
index 0000000..1824815
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/EvaluationReason.scala
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+sealed trait EvaluationReason
+
+object EvaluationReason {
+
+  /** The evaluated value is static (no dynamic evaluation). */
+  case object Static extends EvaluationReason
+
+  /** The evaluated value fell back to a pre-configured value (no dynamic
+    * evaluation occurred or dynamic evaluation yielded no result).
+    */
+  case object Default extends EvaluationReason
+
+  /** The evaluated value was the result of a dynamic evaluation, such as a rule
+    * or specific user-targeting.
+    */
+  case object TargetingMatch extends EvaluationReason
+
+  /** The evaluated value was the result of pseudorandom assignment. */
+  case object Split extends EvaluationReason
+
+  /** The evaluated value was retrieved from cache. */
+  case object Cached extends EvaluationReason
+
+  /** The evaluated value was the result of the flag being disabled in the
+    * management system.
+    */
+  case object Disabled extends EvaluationReason
+
+  /** The reason for the evaluated value could not be determined. */
+  case object Unknown extends EvaluationReason
+
+  /** The evaluated value is non-authoritative or possibly out of date */
+  case object Stale extends EvaluationReason
+
+  /** The evaluated value was the result of an error. */
+  case object Error extends EvaluationReason
+
+  /** Any other provider-defined reason */
+  case class Other(reason: String) extends EvaluationReason
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/FeatureClient.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/FeatureClient.scala
new file mode 100644
index 0000000..087c516
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/FeatureClient.scala
@@ -0,0 +1,189 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+import io.cardell.openfeature.provider.ProviderMetadata
+
+// TODO implement circe
+// trait StructureDecoder[A]
+
+case class EvaluationOptions()
+
+object EvaluationOptions {
+  val Defaults: EvaluationOptions = EvaluationOptions()
+}
+
+trait FeatureClient[F[_]] {
+
+  def providerMetadata: ProviderMetadata
+
+  def evaluationContext: EvaluationContext
+  def withEvaluationContext(context: EvaluationContext): FeatureClient[F]
+
+  // def hooks: List[Hook]
+  // def withHook(hook: Hook): FeatureClient[F]
+  // def withHooks(hooks: List[Hook]): FeatureClient[F]
+
+  def getBooleanValue(flagKey: String, default: Boolean): F[Boolean]
+
+  def getBooleanValue(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext
+  ): F[Boolean]
+
+  def getBooleanValue(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext,
+      options: EvaluationOptions
+  ): F[Boolean]
+
+  def getBooleanDetails(
+      flagKey: String,
+      default: Boolean
+  ): F[EvaluationDetails[Boolean]]
+
+  def getBooleanDetails(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext
+  ): F[EvaluationDetails[Boolean]]
+
+  def getBooleanDetails(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext,
+      options: EvaluationOptions
+  ): F[EvaluationDetails[Boolean]]
+
+  // def getStringValue(flagKey: String, default: String): F[String]
+  // def getStringValue(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext
+  // ): F[String]
+  // def getStringValue(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[String]
+  //
+  // def getStringDetails(
+  //     flagKey: String,
+  //     default: String
+  // ): F[EvaluationDetails[String]]
+  // def getStringDetails(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[String]]
+  // def getStringDetails(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[String]]
+  //
+  // def getIntValue(flagKey: String, default: Int): F[Int]
+  // def getIntValue(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext
+  // ): F[Int]
+  // def getIntValue(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[Int]
+  //
+  // def getIntDetails(flagKey: String, default: Int): F[EvaluationDetails[Int]]
+  // def getIntDetails(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[Int]]
+  // def getIntDetails(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[Int]]
+  //
+  // def getDoubleValue(flagKey: String, default: Double): F[Double]
+  // def getDoubleValue(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext
+  // ): F[Double]
+  // def getDoubleValue(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[Double]
+  //
+  // def getDoubleDetails(
+  //     flagKey: String,
+  //     default: Double
+  // ): F[EvaluationDetails[Double]]
+  // def getDoubleDetails(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[Double]]
+  // def getDoubleDetails(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[Double]]
+  //
+  // def getStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A
+  // ): F[A]
+  // def getStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext
+  // ): F[A]
+  // def getStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[A]
+  //
+  // def getStructureDetails[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A
+  // ): F[EvaluationDetails[A]]
+  // def getStructureDetails[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[A]]
+  // def getStructureDetails[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[A]]
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/FeatureClientImpl.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/FeatureClientImpl.scala
new file mode 100644
index 0000000..ea68066
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/FeatureClientImpl.scala
@@ -0,0 +1,282 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+import cats.Monad
+import cats.syntax.all._
+
+import io.cardell.openfeature.provider.Provider
+import io.cardell.openfeature.provider.ProviderMetadata
+
+protected[openfeature] final class FeatureClientImpl[F[_]: Monad](
+    provider: Provider[F],
+    clientEvaluationContext: EvaluationContext
+) extends FeatureClient[F] {
+
+  override def providerMetadata: ProviderMetadata = provider.metadata
+
+  override def evaluationContext: EvaluationContext = clientEvaluationContext
+
+  override def withEvaluationContext(
+      context: EvaluationContext
+  ): FeatureClient[F] =
+    new FeatureClientImpl[F](provider, clientEvaluationContext ++ context)
+
+  // override def hooks: List[Hook] = ???
+  // override def withHook(hook: Hook): FeatureClient[F] = ???
+  // override def withHooks(hooks: List[Hook]): FeatureClient[F] = ???
+
+  override def getBooleanValue(flagKey: String, default: Boolean): F[Boolean] =
+    getBooleanValue(flagKey, default, EvaluationContext.empty)
+
+  override def getBooleanValue(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext
+  ): F[Boolean] = getBooleanValue(
+    flagKey,
+    default,
+    context,
+    EvaluationOptions.Defaults
+  )
+
+  override def getBooleanValue(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext,
+      options: EvaluationOptions // TODO handle options
+  ): F[Boolean] = getBooleanDetails(flagKey, default, context, options)
+    .map(_.value)
+
+  override def getBooleanDetails(
+      flagKey: String,
+      default: Boolean
+  ): F[EvaluationDetails[Boolean]] = getBooleanDetails(
+    flagKey,
+    default,
+    EvaluationContext.empty
+  )
+
+  override def getBooleanDetails(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext
+  ): F[EvaluationDetails[Boolean]] = getBooleanDetails(
+    flagKey,
+    default,
+    context,
+    EvaluationOptions.Defaults
+  )
+
+  override def getBooleanDetails(
+      flagKey: String,
+      default: Boolean,
+      context: EvaluationContext,
+      options: EvaluationOptions
+  ): F[EvaluationDetails[Boolean]] = provider
+    .resolveBooleanValue(
+      flagKey,
+      default,
+      clientEvaluationContext ++ context
+    )
+    .map(EvaluationDetails[Boolean](flagKey, _))
+
+  // override def getStringValue(flagKey: String, default: String): F[String] =
+  //   getStringValue(flagKey, default, EvaluationContext.empty)
+  //
+  // override def getStringValue(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext
+  // ): F[String] =
+  //   getStringValue(
+  //     flagKey,
+  //     default,
+  //     context,
+  //     EvaluationOptions.Defaults
+  //   )
+  //
+  // override def getStringValue(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[String] =
+  //   getStringDetails(flagKey, default, context, EvaluationOptions.Defaults)
+  //     .map(_.value)
+  //
+  // override def getStringDetails(
+  //     flagKey: String,
+  //     default: String
+  // ): F[EvaluationDetails[String]] =
+  //   getStringDetails(flagKey, default, EvaluationContext.empty)
+  //
+  // override def getStringDetails(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[String]] =
+  //   getStringDetails(flagKey, default, context, EvaluationOptions.Defaults)
+  //
+  // override def getStringDetails(
+  //     flagKey: String,
+  //     default: String,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[String]] =
+  //   provider
+  //     .resolveStringValue(flagKey, default, clientEvaluationContext ++ context)
+  //     .map(EvaluationDetails[String](flagKey, _))
+  //
+  // override def getIntValue(flagKey: String, default: Int): F[Int] =
+  //   getIntValue(flagKey, default, EvaluationContext.empty)
+  //
+  // override def getIntValue(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext
+  // ): F[Int] = getIntValue(flagKey, default, context, EvaluationOptions.Defaults)
+  //
+  // override def getIntValue(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[Int] =
+  //   getIntDetails(flagKey, default, context, options)
+  //     .map(_.value)
+  //
+  // override def getIntDetails(
+  //     flagKey: String,
+  //     default: Int
+  // ): F[EvaluationDetails[Int]] =
+  //   getIntDetails(flagKey, default, EvaluationContext.empty)
+  //
+  // override def getIntDetails(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[Int]] =
+  //   getIntDetails(flagKey, default, context, EvaluationOptions.Defaults)
+  //
+  // override def getIntDetails(
+  //     flagKey: String,
+  //     default: Int,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[Int]] =
+  //   provider
+  //     .resolveIntValue(
+  //       flagKey,
+  //       default,
+  //       clientEvaluationContext ++ context
+  //     )
+  //     .map(EvaluationDetails[Int](flagKey, _))
+  //
+  // override def getDoubleValue(flagKey: String, default: Double): F[Double] =
+  //   getDoubleValue(flagKey, default, EvaluationContext.empty)
+  //
+  // override def getDoubleValue(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext
+  // ): F[Double] =
+  //   getDoubleValue(flagKey, default, context, EvaluationOptions.Defaults)
+  //
+  // override def getDoubleValue(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[Double] =
+  //   provider
+  //     .resolveDoubleValue(
+  //       flagKey,
+  //       default,
+  //       clientEvaluationContext ++ context
+  //     )
+  //     .map(_.value)
+  //
+  // override def getDoubleDetails(
+  //     flagKey: String,
+  //     default: Double
+  // ): F[EvaluationDetails[Double]] = ???
+  // override def getDoubleDetails(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[Double]] = ???
+  // override def getDoubleDetails(
+  //     flagKey: String,
+  //     default: Double,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[Double]] = ???
+  //
+  // override def getStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A
+  // ): F[A] =
+  //   getStructureValue[A](flagKey, default, EvaluationContext.empty)
+  //
+  // override def getStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext
+  // ): F[A] =
+  //   getStructureValue[A](flagKey, default, context, EvaluationOptions.Defaults)
+  //
+  // override def getStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[A] =
+  //   getStructureDetails[A](flagKey, default, context)
+  //     .map(_.value)
+  //
+  // override def getStructureDetails[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A
+  // ): F[EvaluationDetails[A]] =
+  //   getStructureDetails[A](flagKey, default, EvaluationContext.empty)
+  // override def getStructureDetails[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext
+  // ): F[EvaluationDetails[A]] =
+  //   getStructureDetails[A](
+  //     flagKey,
+  //     default,
+  //     context,
+  //     EvaluationOptions.Defaults
+  //   )
+  //
+  // override def getStructureDetails[A: StructureDecoder](
+  //     flagKey: String,
+  //     default: A,
+  //     context: EvaluationContext,
+  //     options: EvaluationOptions
+  // ): F[EvaluationDetails[A]] =
+  //   provider
+  //     .resolveStructureValue[A](
+  //       flagKey,
+  //       default,
+  //       clientEvaluationContext ++ context
+  //     )
+  //     .map(EvaluationDetails(flagKey, _))
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/OpenFeature.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/OpenFeature.scala
new file mode 100644
index 0000000..e155351
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/OpenFeature.scala
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+import cats.Monad
+import cats.syntax.all._
+
+import io.cardell.openfeature.provider.Provider
+
+trait OpenFeature[F[_]] {
+
+  /** Create a client using the default provider
+    */
+  def client: F[FeatureClient[F]]
+}
+
+protected[openfeature] class OpenFeatureSdk[F[_]: Monad](provider: Provider[F])
+    extends OpenFeature[F] {
+
+  def client: F[FeatureClient[F]] =
+    new FeatureClientImpl[F](provider, EvaluationContext.empty).pure[F].widen
+
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/package.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/package.scala
new file mode 100644
index 0000000..58bb1a6
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/package.scala
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell
+
+package object openfeature {}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/Provider.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/Provider.scala
new file mode 100644
index 0000000..2fa35f8
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/Provider.scala
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature.provider
+
+import io.cardell.openfeature.EvaluationContext
+// import io.cardell.openfeature.StructureDecoder
+
+trait Provider[F[_]] {
+  def metadata: ProviderMetadata
+
+  def resolveBooleanValue(
+      flagKey: String,
+      defaultValue: Boolean,
+      context: EvaluationContext
+  ): F[ResolutionDetails[Boolean]]
+
+  // def resolveStringValue(
+  //     flagKey: String,
+  //     defaultValue: String,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[String]]
+  //
+  // def resolveIntValue(
+  //     flagKey: String,
+  //     defaultValue: Int,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[Int]]
+  //
+  // def resolveDoubleValue(
+  //     flagKey: String,
+  //     defaultValue: Double,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[Double]]
+  //
+  // def resolveStructureValue[A: StructureDecoder](
+  //     flagKey: String,
+  //     defaultValue: A,
+  //     context: EvaluationContext
+  // ): F[ResolutionDetails[A]]
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ProviderMetadata.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ProviderMetadata.scala
new file mode 100644
index 0000000..cb14d4c
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ProviderMetadata.scala
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature.provider
+
+case class ProviderMetadata(name: String)
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ProviderStatus.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ProviderStatus.scala
new file mode 100644
index 0000000..0fc466b
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ProviderStatus.scala
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature.provider
+
+sealed trait ProviderStatus
+
+object ProviderStatus {
+
+  /** The provider has not been initialized. */
+  case object NotReady extends ProviderStatus
+
+  /** The provider has been initialized, and is able to reliably resolve flag
+    * values.
+    */
+  case object Ready extends ProviderStatus
+
+  /** The provider is initialized but is not able to reliably resolve flag
+    * values.
+    */
+  case object Error extends ProviderStatus
+
+  /** The provider's cached state is no longer valid and may not be up-to-date
+    * with the source of truth.
+    */
+  case object Stale extends ProviderStatus
+
+  /** The provider has entered an irrecoverable error state. */
+  case object Fatal extends ProviderStatus
+
+  /* The provider is reconciling its state with a context change. */
+  // client-side only
+  // case object Reconciling extends ProviderStatus
+}
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ResolutionDetails.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ResolutionDetails.scala
new file mode 100644
index 0000000..b1bb9ce
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/ResolutionDetails.scala
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature.provider
+
+import io.cardell.openfeature.ErrorCode
+import io.cardell.openfeature.EvaluationReason
+
+sealed trait FlagMetadataValue
+
+object FlagMetadataValue {
+  case class Boolean(value: Boolean) extends FlagMetadataValue
+  case class String(value: String)   extends FlagMetadataValue
+  case class Int(value: String)      extends FlagMetadataValue
+  case class Double(value: Double)   extends FlagMetadataValue
+  // TODO circe unwrapped codecs
+}
+
+case class ResolutionDetails[A](
+    value: A,
+    errorCode: Option[ErrorCode],
+    errorMessage: Option[String],
+    reason: Option[EvaluationReason],
+    variant: Option[String],
+    metadata: Option[FlagMetadata]
+)
diff --git a/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/package.scala b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/package.scala
new file mode 100644
index 0000000..f0b1b98
--- /dev/null
+++ b/open-feature/sdk/src/main/scala/io/cardell/openfeature/provider/package.scala
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2023 Alex Cardell
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.cardell.openfeature
+
+package object provider {
+
+  type FlagMetadata = Map[String, FlagMetadataValue]
+
+}
diff --git a/project/plugins.sbt b/project/plugins.sbt
index d313796..fcd01cd 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,5 +1,5 @@
-addSbtPlugin("org.typelevel" % "sbt-typelevel" % "0.6.7")
-addSbtPlugin("org.typelevel" % "sbt-typelevel-site" % "0.6.7")
-addSbtPlugin("org.typelevel" % "sbt-typelevel-scalafix" % "0.6.7")
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")
-addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.17")
+addSbtPlugin("org.typelevel"    % "sbt-typelevel"          % "0.7.3")
+addSbtPlugin("org.typelevel"    % "sbt-typelevel-site"     % "0.7.3")
+addSbtPlugin("org.typelevel"    % "sbt-typelevel-scalafix" % "0.7.3")
+addSbtPlugin("org.scala-js"     % "sbt-scalajs"            % "1.16.0")
+addSbtPlugin("org.scala-native" % "sbt-scala-native"       % "0.4.17")