diff --git a/doc/rest-nvim.txt b/doc/rest-nvim.txt
index 204c3dca..f5eda774 100644
--- a/doc/rest-nvim.txt
+++ b/doc/rest-nvim.txt
@@ -22,6 +22,7 @@ CONTENTS                                                   *rest-nvim-contents*
         4. Environment Variables........|rest-nvim-usage-environment-variables|
         5. Dynamic Variables................|rest-nvim-usage-dynamic-variables|
         6. Callbacks................................|rest-nvim-usage-callbacks|
+        7. Pre-script..............................|rest-nvim-usage-pre-script|
     5. Known issues..........................................|rest-nvim-issues|
     6. License..............................................|rest-nvim-license|
     7. Contributing....................................|rest-nvim-contributing|
@@ -241,6 +242,31 @@ rest.nvim fires different events upon requests:
     })
 <
 ===============================================================================
+Pre-Script                                           *rest-nvim-usage-pre-script*
+
+rest.nvim allows configuring a pre-script that is invoked before launching a
+request. This script can be used to dynamically modify the request headers and
+body. The script receives the request opts and environment variables: >lua
+
+    -- pre-script example:
+    require("rest-nvim").setup({
+      request = {
+	pre_script = function(opts, variables)
+	  -- Access request body
+	  local body = opts["body"]
+	  -- Access request headers
+	  local content_type = opts["headers"]["Content-Type"]
+	  -- Access environment variables
+	  local secret_key = variables["SECRET_KEY"]
+
+	  -- Set custom request headers.
+	  opts["headers"]["X-Signature"] = signature(body, secret_key)
+	  opts["headers"]["X-Timestamp"] = os.time
+	end
+      },
+    })
+<
+===============================================================================
 KNOWN ISSUES                                                 *rest-nvim-issues*
 
     - Nothing here at the moment :)
diff --git a/lua/rest-nvim/config/init.lua b/lua/rest-nvim/config/init.lua
index 58bf6ece..2ce92eb3 100644
--- a/lua/rest-nvim/config/init.lua
+++ b/lua/rest-nvim/config/init.lua
@@ -10,6 +10,10 @@ local config = {
     enabled = true,
     timeout = 150,
   },
+  request = {
+    pre_script = function()
+    end
+  },
   result = {
     show_curl_command = true,
     show_url = true,
diff --git a/lua/rest-nvim/curl/init.lua b/lua/rest-nvim/curl/init.lua
index cca93790..f5273006 100644
--- a/lua/rest-nvim/curl/init.lua
+++ b/lua/rest-nvim/curl/init.lua
@@ -276,6 +276,12 @@ end
 --           - yank_dry_run (boolean): displays the command
 --           - arguments are forwarded to plenary
 M.curl_cmd = function(opts)
+
+  --- Execute request pre-script if any.
+  if config.get("request").pre_script then
+    config.get("request").pre_script(opts, utils.get_variables())
+  end
+
   -- plenary's curl module is strange in the sense that with "dry_run" it returns the command
   -- otherwise it starts the request :/
   local dry_run_opts = vim.tbl_extend("force", opts, { dry_run = true })
diff --git a/lua/telescope/_extensions/rest.lua b/lua/telescope/_extensions/rest.lua
index f2a0f1f6..c91521d7 100644
--- a/lua/telescope/_extensions/rest.lua
+++ b/lua/telescope/_extensions/rest.lua
@@ -16,7 +16,7 @@ local conf = require("telescope.config").values
 
 local config = require("rest-nvim.config")
 
-local function rest_env_select(opt)
+local function rest_env_select(_)
   local pattern = config.get("env_pattern")
   local edit = config.get("env_edit_command")