diff --git a/.github/workflows/asv.yml b/.github/workflows/asv.yml
index aca239e935..3b3167a6c4 100644
--- a/.github/workflows/asv.yml
+++ b/.github/workflows/asv.yml
@@ -27,10 +27,9 @@ jobs:
       with:
         python-version: "3.10"
 
-    - uses: actions-rs/toolchain@v1
-      with:
-        toolchain: stable
-        override: true
+    - uses: dtolnay/rust-toolchain@stable
+
+    - uses: Swatinem/rust-cache@v2
 
     - name: Install dependencies
       run: |
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 459f29ece2..354866775f 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -15,17 +15,13 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v4
 
-      - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: Swatinem/rust-cache@v2
 
       - name: Run cargo check
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
+        run: |
+          cargo check
 
   test:
     runs-on: ${{ matrix.os }}
@@ -53,32 +49,30 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
-          override: true
+
+      - uses: Swatinem/rust-cache@v2
+
+      - uses: taiki-e/install-action@nextest
 
       - name: Run tests
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --no-fail-fast
+        run: |
+          cargo nextest run
 
   test_all_features:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: Swatinem/rust-cache@v2
 
-      - uses: actions-rs/install@v0.1
+      - uses: taiki-e/install-action@v2
         with:
-          crate: cargo-all-features
-          version: latest
-          use-tool-cache: true
+          tool: cargo-all-features
 
       - name: Run tests for all feature combinations
         run: cargo test-all-features --no-fail-fast --all
@@ -88,29 +82,23 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
         with:
-          toolchain: stable
-          override: true
+          components: llvm-tools-preview
+      - uses: Swatinem/rust-cache@v2
 
-      - name: Install cargo-binstall
-        run: |
-          wget https://github.com/ryankurte/cargo-binstall/releases/latest/download/cargo-binstall-x86_64-unknown-linux-gnu.tgz
-          tar xf cargo-binstall-x86_64-unknown-linux-gnu.tgz
-          chmod +x cargo-binstall
-          mv cargo-binstall "$HOME/.cargo/bin"
-
-      - name: Install cargo-tarpaulin
-        run: cargo binstall --no-confirm cargo-tarpaulin
+      - uses: taiki-e/install-action@cargo-llvm-cov
+      - uses: taiki-e/install-action@nextest
 
-      - name: Coverage with tarpaulin
-        run: cargo tarpaulin --all --all-features --timeout 600 --out xml -- --test-threads 1
+      - name: Collect coverage data
+        run: cargo llvm-cov nextest --all-features --lcov --output-path lcov.info
 
       - name: Upload Rust coverage to codecov
         uses: codecov/codecov-action@v3
         with:
           flags: rust
           fail_ci_if_error: true
+          files: lcov.info
 
   lints:
     name: Lints
@@ -129,24 +117,20 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Rust toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@master
         with:
-          profile: minimal
           toolchain: ${{ matrix.rust }}
-          override: true
-          components: rustfmt, clippy
+          components: "clippy, rustfmt"
+
+      - uses: Swatinem/rust-cache@v2
 
       - name: Run cargo fmt
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
+        run: |
+          cargo fmt --all -- --check
 
       - name: Run cargo clippy
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --all -- -D warnings
+        run: |
+          cargo clippy --all -- -D warnings
 
   wasm-pack:
     name: Check if wasm-pack builds a valid package for the sourmash crate
@@ -154,11 +138,12 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
         with:
-          toolchain: stable
           target: wasm32-unknown-unknown
 
+      - uses: Swatinem/rust-cache@v2
+
       - name: Install wasm-pack
         run: "curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh"
 
@@ -190,38 +175,6 @@ jobs:
         with:
           path: 'pkg/sourmash*.tgz'
 
-  wasm32-wasi:
-    name: Run tests under wasm32-wasi
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Install wasm32-wasi target
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          target: wasm32-wasi
-      - name: Install wasmtime
-        run: "curl https://wasmtime.dev/install.sh -sSf | bash"
-      - name: Add wasmtime to PATH
-        run: echo "$HOME/.wasmtime/bin" >> $GITHUB_PATH
-      - name: Install cargo-wasi command
-        uses: actions-rs/cargo@v1
-        with:
-          command: install
-          args: --force cargo-wasi
-      - name: Build code with cargo-wasi
-        uses: actions-rs/cargo@v1
-        continue-on-error: true  ## TODO: remove this when build works...
-        with:
-          command: wasi
-          args: build
-      - name: Run tests under wasm32-wasi
-        uses: actions-rs/cargo@v1
-        continue-on-error: true  ## TODO: remove this when tests work...
-        with:
-          command: wasi
-          args: test
-
   publish:
     name: Publish (on tags, dry-run otherwise)
     runs-on: ubuntu-latest
@@ -229,12 +182,9 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v4
 
-      - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: Swatinem/rust-cache@v2
 
       - name: Check semver
         uses: obi1kenobi/cargo-semver-checks-action@v2
@@ -245,45 +195,38 @@ jobs:
           features: branchwater
 
       - name: Make sure we can publish the sourmash crate
-        uses: actions-rs/cargo@v1
-        with:
-          command: publish
-          args: --dry-run --manifest-path src/core/Cargo.toml
+        run: |
+          cargo publish --dry-run --manifest-path src/core/Cargo.toml
 
       # Login to crates.io on tags
       - name: login to crates.io
-        uses: actions-rs/cargo@v1
         if: startsWith(github.ref, 'refs/tags/r')
-        with:
-          command: login
-          args: ${{ secrets.CRATES_IO_TOKEN }}
+        run: |
+          cargo login ${{ secrets.CRATES_IO_TOKEN }}
 
       # Publish to crates.io on tags
       - name: Publish to crates.io
         if: startsWith(github.ref, 'refs/tags/r')
-        uses: actions-rs/cargo@v1
-        with:
-          command: publish
-          args: --manifest-path src/core/Cargo.toml
+        run: |
+          cargo publish --manifest-path src/core/Cargo.toml
 
   minimum_rust_version:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: "1.66.0"
-          override: true
+
+      - uses: Swatinem/rust-cache@v2
 
       - name: check if README matches MSRV defined here
         run: grep '1.66.0' src/core/README.md
 
       - name: Check if it builds properly
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --all-features
+        run: |
+          cargo build --all-features
 
   check_cbindgen:
     name: "Check if cbindgen runs cleanly for generating the C headers"
@@ -291,16 +234,13 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: Swatinem/rust-cache@v2
 
-      - uses: actions-rs/install@v0.1
+      - uses: taiki-e/install-action@v2
         with:
-          crate: cbindgen
-          version: 0.20.0
-          use-tool-cache: true
+          tool: cbindgen@0.20.0
 
       - run: make include/sourmash.h
 
diff --git a/flake.lock b/flake.lock
index 41f929d8e7..eb0632cfe2 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1728979988,
-        "narHash": "sha256-GBJRnbFLDg0y7ridWJHAP4Nn7oss50/VNgqoXaf/RVk=",
+        "lastModified": 1736241350,
+        "narHash": "sha256-CHd7yhaDigUuJyDeX0SADbTM9FXfiWaeNyY34FL1wQU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "7881fbfd2e3ed1dfa315fca889b2cfd94be39337",
+        "rev": "8c9fd3e564728e90829ee7dbac6edc972971cd0f",
         "type": "github"
       },
       "original": {
@@ -30,11 +30,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1729184663,
-        "narHash": "sha256-uNyi5vQrzaLkt4jj6ZEOs4+4UqOAwP6jFG2s7LIDwIk=",
+        "lastModified": 1736303309,
+        "narHash": "sha256-IKrk7RL+Q/2NC6+Ql6dwwCNZI6T6JH2grTdJaVWHF0A=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "16fb78d443c1970dda9a0bbb93070c9d8598a925",
+        "rev": "a0b81d4fa349d9af1765b0f0b4a899c13776f706",
         "type": "github"
       },
       "original": {
@@ -63,11 +63,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1726560853,
-        "narHash": "sha256-X6rJYSESBVr3hBoH0WbKE5KvhPU5bloyZ2L4K60/fPQ=",
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "c1dfcf08411b08f6b8615f7d8971a2bfa81d5e8a",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 732f4b59de..e8b647b999 100644
--- a/flake.nix
+++ b/flake.nix
@@ -21,8 +21,9 @@
         };
         rustVersion = pkgs.rust-bin.stable.latest.default.override {
           #extensions = [ "rust-src" ];
+          extensions = [ "llvm-tools-preview" ];
           #targets = [ "x86_64-unknown-linux-musl" ];
-          targets = [ "wasm32-wasi" "wasm32-unknown-unknown" "wasm32-unknown-emscripten" ];
+          targets = [ "wasm32-unknown-unknown" "wasm32-unknown-emscripten" ];
         };
         rustPlatform = pkgs.makeRustPlatform {
           cargo = rustVersion;
@@ -122,7 +123,9 @@
             cargo-outdated
             cargo-udeps
             cargo-deny
-            cargo-wasi
+            cargo-nextest
+            cargo-llvm-cov
+            cargo-component
             cargo-codspeed
             cargo-semver-checks
             nixpkgs-fmt