diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## Req 3.7.0
+
+* Added `reqCb`, a function that allows you to modify the `Request` object
+  but otherwise performs the requst for you.
+
+* Derived `MonadThrow`, `MonadCatch`, and `MonadMask` for the `Req` monad.
+
 ## Req 3.6.0
 
 * Added the `httpConfigBodyPreviewLength` configuration parameter to
diff --git a/Network/HTTP/Req.hs b/Network/HTTP/Req.hs
--- a/Network/HTTP/Req.hs
+++ b/Network/HTTP/Req.hs
@@ -14,6 +14,7 @@
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE RoleAnnotations #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE TemplateHaskellQuotes #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UndecidableInstances #-}
@@ -112,6 +113,7 @@
     -- $making-a-request
     req,
     reqBr,
+    reqCb,
     req',
     withReqManager,
 
@@ -235,7 +237,7 @@
 import Control.Arrow (first, second)
 import Control.Exception hiding (Handler (..), TypeError)
 import Control.Monad.Base
-import Control.Monad.Catch (Handler (..))
+import Control.Monad.Catch (Handler (..), MonadCatch, MonadMask, MonadThrow)
 import Control.Monad.IO.Class
 import Control.Monad.IO.Unlift
 import Control.Monad.Reader
@@ -429,12 +431,7 @@
   -- | Response
   m response
 req method url body responseProxy options =
-  reqBr method url body (options <> extraOptions) getHttpResponse
-  where
-    extraOptions =
-      case acceptHeader responseProxy of
-        Nothing -> mempty
-        Just accept -> header "Accept" accept
+  reqCb method url body responseProxy options pure
 
 -- | A version of 'req' that does not use one of the predefined instances of
 -- 'HttpResponse' but instead allows the user to consume @'L.Response'
@@ -459,7 +456,58 @@
   (L.Response L.BodyReader -> IO a) ->
   -- | Result
   m a
-reqBr method url body options consume = req' method url body options $ \request manager -> do
+reqBr method url body options consume =
+  req' method url body options (reqHandler consume)
+
+-- | A version of 'req' that takes a callback to modify the 'L.Request', but
+-- otherwise performs the request identically.
+--
+-- @since 3.7.0
+reqCb ::
+  ( MonadHttp m,
+    HttpMethod method,
+    HttpBody body,
+    HttpResponse response,
+    HttpBodyAllowed (AllowsBody method) (ProvidesBody body)
+  ) =>
+  -- | HTTP method
+  method ->
+  -- | 'Url'—location of resource
+  Url scheme ->
+  -- | Body of the request
+  body ->
+  -- | A hint how to interpret response
+  Proxy response ->
+  -- | Collection of optional parameters
+  Option scheme ->
+  -- | Callback to modify the request
+  (L.Request -> m L.Request) ->
+  -- | Response
+  m response
+reqCb method url body responseProxy options adjustRequest =
+  req' method url body (options <> extraOptions) $ \request manager -> do
+    request' <- adjustRequest request
+    reqHandler getHttpResponse request' manager
+  where
+    extraOptions =
+      case acceptHeader responseProxy of
+        Nothing -> mempty
+        Just accept -> header "Accept" accept
+
+-- | The default handler function that the higher-level request functions
+-- pass to 'req''. Internal function.
+--
+-- @since 3.7.0
+reqHandler ::
+  MonadHttp m =>
+  -- | How to get final result from a 'L.Response'
+  (L.Response L.BodyReader -> IO b) ->
+  -- | 'L.Request' to perform
+  L.Request ->
+  -- | 'L.Manager' to use
+  L.Manager ->
+  m b
+reqHandler consume request manager = do
   HttpConfig {..} <- getHttpConfig
   let wrapVanilla = handle (throwIO . VanillaHttpException)
       wrapExc = handle (throwIO . LI.toHttpException request)
@@ -728,6 +776,15 @@
       MonadIO,
       MonadUnliftIO
     )
+
+-- | @since 3.7.0
+deriving instance MonadThrow Req
+
+-- | @since 3.7.0
+deriving instance MonadCatch Req
+
+-- | @since 3.7.0
+deriving instance MonadMask Req
 
 instance MonadBase IO Req where
   liftBase = liftIO
diff --git a/req.cabal b/req.cabal
--- a/req.cabal
+++ b/req.cabal
@@ -1,11 +1,11 @@
 cabal-version:   1.18
 name:            req
-version:         3.6.0
+version:         3.7.0
 license:         BSD3
 license-file:    LICENSE.md
 maintainer:      Mark Karpov <markkarpov92@gmail.com>
 author:          Mark Karpov <markkarpov92@gmail.com>
-tested-with:     ghc ==8.6.5 ghc ==8.8.4 ghc ==8.10.1
+tested-with:     ghc ==8.6.5 ghc ==8.8.4 ghc ==8.10.2
 homepage:        https://github.com/mrkkrp/req
 bug-reports:     https://github.com/mrkkrp/req/issues
 synopsis:
@@ -122,7 +122,7 @@
         mtl >=2.0 && <3.0,
         req -any,
         text >=0.2 && <1.3,
-        unordered-containers >=0.2.5 && <0.2.13
+        unordered-containers >=0.2.5 && <0.3
 
     if flag(dev)
         ghc-options: -O0 -Wall -Werror