diff --git a/client/spago.dhall b/client/spago.dhall
index 8cfd517e..dddfd3f7 100644
--- a/client/spago.dhall
+++ b/client/spago.dhall
@@ -4,12 +4,15 @@ You can edit this file as you like.
 -}
 { name = "try-purescript"
 , dependencies =
-  [ "arrays"
+  [ "aff"
+  , "affjax"
+  , "arrays"
   , "bifunctors"
   , "console"
   , "const"
   , "contravariant"
   , "control"
+  , "debug"
   , "distributive"
   , "effect"
   , "either"
diff --git a/client/src/Main.purs b/client/src/Main.purs
index cc5d7b15..e44fddec 100644
--- a/client/src/Main.purs
+++ b/client/src/Main.purs
@@ -2,7 +2,6 @@ module Main where
 
 import Prelude
 
-import Control.Monad.Cont.Trans (ContT(..), runContT)
 import Control.Monad.Except.Trans (runExceptT)
 import Data.Array (mapMaybe)
 import Data.Array as Array
@@ -11,6 +10,8 @@ import Data.Foldable (elem, fold, for_, intercalate, traverse_)
 import Data.FoldableWithIndex (forWithIndex_)
 import Data.Maybe (Maybe(..), fromMaybe)
 import Effect (Effect)
+import Effect.Aff (Aff, launchAff_)
+import Effect.Class (liftEffect)
 import Effect.Console (error)
 import Effect.Uncurried (EffectFn1, EffectFn2, EffectFn5, mkEffectFn1, runEffectFn1, runEffectFn2, runEffectFn5)
 import Foreign (renderForeignError)
@@ -132,31 +133,32 @@ compile = do
   displayLoadingMessage
   clearAnnotations
 
-  runContT (runExceptT (API.compile Config.compileUrl code)) \res_ ->
+  launchAff_ $ runExceptT (API.compile Config.compileUrl code) >>= \res_ ->
     case res_ of
-      Left err -> displayPlainText err
+      Left err -> liftEffect $ displayPlainText err
       Right res -> do
-        cleanUpMarkers
+        liftEffect cleanUpMarkers
 
         case res of
           Right (CompileSuccess (SuccessResult { js, warnings })) -> do
-            showJs <- isShowJsChecked
-            if showJs
-              then do hideLoadingMessage
-                      displayPlainText js
-              else runContT (runExceptT $ runLoader loader (JS js)) \sources -> do
-                     hideLoadingMessage
-                     for_ warnings \warnings_ -> do
-                       let toAnnotation (CompileWarning{ errorCode, position, message }) =
-                             position <#> \(ErrorPosition pos) ->
-                               { row: pos.startLine - 1
-                               , column: pos.startColumn - 1
-                               , type: "warning"
-                               , text: message
-                               }
-                       runEffectFn1 setAnnotations (mapMaybe toAnnotation warnings_)
-                     for_ sources (execute (JS js))
-          Right (CompileFailed (FailedResult { error })) -> do
+            showJs <- liftEffect isShowJsChecked
+            if showJs then liftEffect do
+              hideLoadingMessage
+              displayPlainText js
+            else do
+              sources <- runExceptT $ runLoader loader (JS js)
+              liftEffect hideLoadingMessage
+              for_ warnings \warnings_ -> liftEffect do
+                let toAnnotation (CompileWarning{ errorCode, position, message }) =
+                      position <#> \(ErrorPosition pos) ->
+                        { row: pos.startLine - 1
+                        , column: pos.startColumn - 1
+                        , type: "warning"
+                        , text: message
+                        }
+                runEffectFn1 setAnnotations (mapMaybe toAnnotation warnings_)
+              for_ sources (liftEffect <<< execute (JS js))
+          Right (CompileFailed (FailedResult { error })) -> liftEffect do
             hideLoadingMessage
             case error of
               CompilerErrors errs -> do
@@ -180,7 +182,7 @@ compile = do
                       pos.endLine
                       pos.endColumn
               OtherError err -> displayPlainText err
-          Left errs -> do
+          Left errs -> liftEffect do
             hideLoadingMessage
             displayPlainText "Unable to parse the response from the server"
             traverse_ (error <<< renderForeignError) errs
@@ -196,7 +198,6 @@ execute js modules = do
 setupEditor :: forall r. { code :: String | r } -> Effect Unit
 setupEditor { code } = do
   loadOptions
-
   setTextAreaContent code
   runEffectFn1 setEditorContent code
 
@@ -214,34 +215,32 @@ setupEditor { code } = do
     compile
 
   JQuery.select "#gist_save" >>= JQuery.on "click" \e _ ->
-    publishNewGist
+    launchAff_ publishNewGist
 
   compile
   cacheCurrentCode
 
 loadFromGist
   :: String
-  -> ({ code :: String } -> Effect Unit)
-  -> Effect Unit
-loadFromGist id_ k = do
-  runContT (runExceptT (getGistById id_ >>= \gi -> tryLoadFileFromGist gi "Main.purs")) $
-    case _ of
-      Left err -> do
-        window >>= alert err
-        k { code: "" }
-      Right code -> k { code }
+  -> Aff { code :: String }
+loadFromGist id = do
+  runExceptT (getGistById id >>= \gi -> tryLoadFileFromGist gi "Main.purs") >>= case _ of
+    Left err -> do
+      liftEffect $ window >>= alert err
+      pure { code: "" }
+    Right code ->
+      pure { code }
 
 withSession
   :: String
-  -> ({ code :: String } -> Effect Unit)
-  -> Effect Unit
-withSession sessionId k = do
-  state <- tryRetrieveSession sessionId
+  -> Aff { code :: String }
+withSession sessionId = do
+  state <- liftEffect $ tryRetrieveSession sessionId
   case state of
-    Just state' -> k state'
+    Just state' -> pure state'
     Nothing -> do
-      gist <- fromMaybe Config.mainGist <$> getQueryStringMaybe "gist"
-      loadFromGist gist k
+      gist <- liftEffect $ fromMaybe Config.mainGist <$> getQueryStringMaybe "gist"
+      loadFromGist gist
 
 -- | Cache the current code in the session state
 cacheCurrentCode :: Effect Unit
@@ -254,22 +253,21 @@ cacheCurrentCode  = do
     Nothing -> error "No session ID"
 
 -- | Create a new Gist using the current content
-publishNewGist :: Effect Unit
+publishNewGist :: Aff Unit
 publishNewGist = do
-  ok <- window >>= confirm (intercalate "\n"
+  ok <- liftEffect $ window >>= confirm (intercalate "\n"
           [ "Do you really want to publish this code as an anonymous Gist?"
           , ""
           , "Note: this code will be available to anyone with a link to the Gist."
           ])
   when ok do
-    content <- getTextAreaContent
-    runContT (runExceptT (uploadGist content)) $
-      case _ of
-        Left err -> do
-          window >>= alert "Failed to create gist"
-          error ("Failed to create gist: " <> err)
-        Right gistId -> do
-          setQueryStrings (Object.singleton "gist" gistId)
+    content <- liftEffect $ getTextAreaContent
+    runExceptT (uploadGist content) >>= case _ of
+      Left err -> liftEffect do
+        window >>= alert "Failed to create gist"
+        error ("Failed to create gist: " <> err)
+      Right gistId -> liftEffect do
+        setQueryStrings (Object.singleton "gist" gistId)
 
 -- | Navigate to the specified URL.
 navigateTo :: String -> Effect Unit
@@ -308,5 +306,6 @@ main = JQuery.ready do
     viewMode <- JQueryExtras.filter jq ":checked" >>= JQueryExtras.getValueMaybe
     changeViewMode viewMode
 
-  runContT (do sessionId <- ContT createSessionIdIfNecessary
-               ContT (withSession sessionId)) setupEditor
+  createSessionIdIfNecessary \sessionId -> launchAff_ do
+    code <- withSession sessionId
+    liftEffect $ setupEditor code
diff --git a/client/src/Try/API.js b/client/src/Try/API.js
deleted file mode 100644
index a00c83f8..00000000
--- a/client/src/Try/API.js
+++ /dev/null
@@ -1,23 +0,0 @@
-"use strict";
-
-exports.get_ = function(uri, done, fail) {
-  $.get(uri).done(done).fail(function(err) {
-    fail(err.statusText);
-  });
-};
-
-exports.compile_ = function(endpoint, code, done, fail) {
-  $.ajax({
-    url: endpoint + '/compile',
-    dataType: 'json',
-    data: code,
-    method: 'POST',
-    contentType: 'text/plain',
-    success: function(res) {
-      done(res);
-    },
-    error: function(res) {
-      fail(res.responseText)
-    }
-  });
-}
diff --git a/client/src/Try/API.purs b/client/src/Try/API.purs
index ccb920eb..2f470704 100644
--- a/client/src/Try/API.purs
+++ b/client/src/Try/API.purs
@@ -13,17 +13,19 @@ module Try.API
 
 import Prelude
 
+import Affjax (URL, printError)
+import Affjax as AX
+import Affjax.RequestBody as AXRB
+import Affjax.ResponseFormat as AXRF
+import Affjax.StatusCode (StatusCode(..))
 import Control.Alt ((<|>))
-import Control.Monad.Cont.Trans (ContT(ContT))
-import Control.Monad.Except (runExcept)
-import Control.Monad.Except.Trans (ExceptT(ExceptT))
+import Control.Monad.Except (ExceptT(..), runExcept)
 import Data.Either (Either(..))
 import Data.Generic.Rep (class Generic)
 import Data.List.NonEmpty (NonEmptyList)
-import Data.Maybe (Maybe)
-import Effect (Effect)
-import Effect.Uncurried (EffectFn1, EffectFn3, EffectFn4, mkEffectFn1, runEffectFn3, runEffectFn4)
-import Foreign (Foreign, ForeignError)
+import Data.Maybe (Maybe(..))
+import Effect.Aff (Aff)
+import Foreign (ForeignError, unsafeToForeign)
 import Foreign.Class (class Decode, decode)
 import Foreign.Generic (defaultOptions, genericDecode)
 import Foreign.Generic.Class (Options, SumEncoding(..))
@@ -123,31 +125,23 @@ instance decodeCompileResult :: Decode CompileResult where
     CompileSuccess <$> genericDecode decodingOptions f
     <|> CompileFailed <$> genericDecode decodingOptions f
 
-foreign import get_
-  :: EffectFn3
-            String
-            (EffectFn1 String Unit)
-            (EffectFn1 String Unit)
-            Unit
-
--- | A wrapper for `get` which uses `ContT`.
-get :: String -> ExceptT String (ContT Unit Effect) String
-get uri = ExceptT (ContT \k -> runEffectFn3 get_ uri (mkEffectFn1 (k <<< Right)) (mkEffectFn1 (k <<< Left)))
-
--- | POST the specified code to the Try PureScript API, and wait for
--- | a response.
-foreign import compile_
-  :: EffectFn4
-            String
-            String
-            (EffectFn1 Foreign Unit)
-            (EffectFn1 String Unit)
-            Unit
-
--- | A wrapper for `compileApi` which uses `ContT`.
-compile
-  :: String
-  -> String
-  -> ExceptT String (ContT Unit Effect)
-       (Either (NonEmptyList ForeignError) CompileResult)
-compile endpoint code = ExceptT (ContT \k -> runEffectFn4 compile_ endpoint code (mkEffectFn1 (k <<< Right <<< runExcept <<< decode)) (mkEffectFn1 (k <<< Left)))
+get :: URL -> ExceptT String Aff String
+get url = ExceptT $ AX.get AXRF.string url >>= case _ of
+  Left e ->
+    pure $ Left $ printError e
+  Right { status } | status >= StatusCode 400 ->
+    pure $ Left $ "Received error status code: " <> show status
+  Right { body } ->
+    pure $ Right body
+
+-- | POST the specified code to the Try PureScript API, and wait for a response.
+compile :: String -> String -> ExceptT String Aff (Either (NonEmptyList ForeignError) CompileResult)
+compile endpoint code = ExceptT $ AX.post AXRF.json (endpoint <> "/compile") (Just requestBody) >>= case _ of
+  Left e ->
+    pure $ Left $ printError e
+  Right { status } | status >= StatusCode 400 ->
+    pure $ Left $ "Received error status code: " <> show status
+  Right { body } ->
+    pure $ Right $ runExcept (decode (unsafeToForeign body))
+  where
+  requestBody = AXRB.String code
diff --git a/client/src/Try/Gist.js b/client/src/Try/Gist.js
index 003adac1..909b5413 100644
--- a/client/src/Try/Gist.js
+++ b/client/src/Try/Gist.js
@@ -1,48 +1,9 @@
 "use strict";
 
-exports.getGistById_ = function(id, done, fail) {
-  $.ajax({
-    url: 'https://api.github.com/gists/' + id,
-    dataType: 'json'
-  }).done(done).fail(function(err) {
-    fail("Unable to load Gist metadata");
-  });
-}
-
-exports.tryLoadFileFromGist_ = function(gistInfo, filename, done, fail) {
+exports.rawUrl_ = function (gistInfo, filename) {
   if (gistInfo.files && gistInfo.files.hasOwnProperty(filename)) {
-    var url = gistInfo.files[filename].raw_url;
-
-    return $.ajax({
-      url: url,
-      dataType: 'text'
-    }).done(done).fail(function(err) {
-      fail(err.statusText);
-    });
+    return gistInfo.files[filename].raw_url;
   } else {
-    fail("Gist does not contain a file named " + filename);
+    return null;
   }
 };
-
-exports.uploadGist_ = function(content, done, fail) {
-  var data = {
-    "description": "Published with try.purescript.org",
-    "public": false,
-    "files": {
-      "Main.purs": {
-        "content": content
-      }
-    }
-  };
-
-  $.ajax({
-    url: 'https://api.github.com/gists',
-    type: 'POST',
-    dataType: 'json',
-    data: JSON.stringify(data)
-  }).success(function(e) {
-    done(e.id);
-  }).error(function(e) {
-    fail(e);
-  });
-};
diff --git a/client/src/Try/Gist.purs b/client/src/Try/Gist.purs
index 6057e291..ac8abb4e 100644
--- a/client/src/Try/Gist.purs
+++ b/client/src/Try/Gist.purs
@@ -5,45 +5,74 @@ module Try.Gist
   , tryLoadFileFromGist
   ) where
 
--- | An abstract data type representing the data we get back from the GitHub API.
 import Prelude
 
-import Control.Monad.Cont.Trans (ContT(..))
+import Affjax (printError)
+import Affjax as AX
+import Affjax.RequestBody as AXRB
+import Affjax.ResponseFormat as AXRF
+import Affjax.StatusCode (StatusCode(..))
 import Control.Monad.Except.Trans (ExceptT(..))
+import Data.Argonaut.Core (Json, caseJsonObject, stringify, toString)
 import Data.Either (Either(..))
-import Effect (Effect)
-import Effect.Uncurried (EffectFn1, EffectFn3, EffectFn4, mkEffectFn1, runEffectFn3, runEffectFn4)
+import Data.Function.Uncurried (Fn2, runFn2)
+import Data.Maybe (Maybe(..))
+import Data.Nullable (Nullable, toMaybe)
+import Effect.Aff (Aff)
+import Foreign.Generic (encodeJSON)
+import Foreign.Object as Object
+import Unsafe.Coerce (unsafeCoerce)
 
 -- | An abstract data type representing the data we get back from the GitHub API.
 data GistInfo
 
-foreign import uploadGist_
-  :: EffectFn3 String
-               (EffectFn1 String Unit)
-               (EffectFn1 String Unit)
-               Unit
-
--- | A wrapper for `uploadGist` which uses `ContT`.
-uploadGist :: String -> ExceptT String (ContT Unit Effect) String
-uploadGist content = ExceptT (ContT \k -> runEffectFn3 uploadGist_ content (mkEffectFn1 (k <<< Right)) (mkEffectFn1 (k <<< Left)))
-
--- | Get a gist by its ID
-foreign import getGistById_
-  :: EffectFn3 String
-               (EffectFn1 GistInfo Unit)
-               (EffectFn1 String Unit)
-               Unit
-
--- | A wrapper for `getGistById` which uses `ContT`.
-getGistById :: String -> ExceptT String (ContT Unit Effect) GistInfo
-getGistById id_ = ExceptT (ContT \k -> runEffectFn3 getGistById_ id_ (mkEffectFn1 (k <<< Right)) (mkEffectFn1 (k <<< Left)))
-
-foreign import tryLoadFileFromGist_
-  :: EffectFn4 GistInfo
-               String
-               (EffectFn1 String Unit)
-               (EffectFn1 String Unit)
-               Unit
-
-tryLoadFileFromGist :: GistInfo -> String -> ExceptT String (ContT Unit Effect) String
-tryLoadFileFromGist gi filename = ExceptT (ContT \k -> runEffectFn4 tryLoadFileFromGist_ gi filename (mkEffectFn1 (k <<< Right)) (mkEffectFn1 (k <<< Left)))
+foreign import rawUrl_ :: Fn2 GistInfo String (Nullable String)
+
+-- | Retrieve the URL for the raw contents of a particular file within a gist,
+-- | if that file exists as part of the gist.
+rawUrl :: GistInfo -> String -> Either String String
+rawUrl gist filename = case toMaybe $ runFn2 rawUrl_ gist filename of
+  Nothing ->
+    Left $ "Gist does not contain a file named " <> filename
+  Just url ->
+    Right url
+
+uploadGist :: String -> ExceptT String Aff String
+uploadGist content = ExceptT $ AX.post AXRF.json "https://api.github.com/gists" requestBody >>= case _ of
+  Left e ->
+    pure $ Left $ "Unable to load Gist metadata: \n" <> printError e
+  Right { status } | status >= StatusCode 400 ->
+    pure $ Left $ "Received error status code: " <> show status
+  Right { body } ->
+    pure $ body # caseJsonObject (Left $ "Expected object in uploadGist, received: " <> stringify body) \obj ->
+      case Object.lookup "id" obj of
+        Just v | Just v' <- toString v -> Right v'
+        Nothing -> Left "No id key found."
+        _ -> Left "Key id was not a string."
+
+  where
+  requestBody = Just $ AXRB.string $ encodeJSON
+    { description: "Published with try.purescript.org"
+    , public: false
+    , files: { "Main.purs": { content } }
+    }
+
+getGistById :: String -> ExceptT String Aff GistInfo
+getGistById id = ExceptT $ AX.get AXRF.json ("https://api.github.com/gists/" <> id) >>= case _ of
+  Left e ->
+    pure $ Left $ "Unable to load Gist metadata: \n" <> printError e
+  Right { status } | status >= StatusCode 400 ->
+    pure $ Left $ "Received error status code: " <> show status
+  Right { body } ->
+    pure $ Right $ (unsafeCoerce :: Json -> GistInfo) body
+
+tryLoadFileFromGist :: GistInfo -> String -> ExceptT String Aff String
+tryLoadFileFromGist gi filename = do
+  url <- ExceptT $ pure $ rawUrl gi filename
+  ExceptT $ AX.get AXRF.string url >>= case _ of
+    Left e ->
+      pure $ Left $ "Unable to load gist contents: \n" <> printError e
+    Right { status } | status >= StatusCode 400 ->
+      pure $ Left $ "Received error status code: " <> show status
+    Right { body } ->
+      pure $ Right body
diff --git a/client/src/Try/Loader.purs b/client/src/Try/Loader.purs
index c26f1fd2..b392829b 100644
--- a/client/src/Try/Loader.purs
+++ b/client/src/Try/Loader.purs
@@ -7,7 +7,6 @@ module Try.Loader
 import Prelude
 
 import Control.Bind (bindFlipped)
-import Control.Monad.Cont (ContT)
 import Control.Monad.Except (ExceptT)
 import Control.Parallel (parTraverse)
 import Data.Array as Array
@@ -22,6 +21,7 @@ import Data.String.Regex.Flags (noFlags)
 import Data.String.Regex.Unsafe (unsafeRegex)
 import Data.Tuple (Tuple(..))
 import Effect (Effect)
+import Effect.Aff (Aff)
 import Effect.Class (liftEffect)
 import Effect.Ref (Ref)
 import Effect.Ref as Ref
@@ -75,9 +75,9 @@ parseDeps current = Array.mapMaybe go <<< String.split (Pattern "\n") <<< unwrap
         , path: Nothing
         }
 
-newtype Loader = Loader (JS -> ExceptT String (ContT Unit Effect) (Object JS))
+newtype Loader = Loader (JS -> ExceptT String Aff (Object JS))
 
-runLoader :: Loader -> JS -> ExceptT String (ContT Unit Effect) (Object JS)
+runLoader :: Loader -> JS -> ExceptT String Aff (Object JS)
 runLoader (Loader k) = k
 
 makeLoader :: String -> Loader
@@ -92,7 +92,7 @@ makeLoader rootPath = Loader (go Object.empty <<< parseDeps "<file>")
   getModule :: String -> Effect (Maybe Module)
   getModule a = Object.lookup a <$> Ref.read moduleCache
 
-  load :: Dependency -> ExceptT String (ContT Unit Effect) Module
+  load :: Dependency -> ExceptT String Aff Module
   load { name, path } = do
     cached <- liftEffect $ getModule name
     case cached of
@@ -116,7 +116,7 @@ makeLoader rootPath = Loader (go Object.empty <<< parseDeps "<file>")
         liftEffect $ putModule name mod
         pure mod
 
-  go :: Object JS -> Array Dependency -> ExceptT String (ContT Unit Effect) (Object JS)
+  go :: Object JS -> Array Dependency -> ExceptT String Aff (Object JS)
   go ms []   = pure ms
   go ms deps = do
     modules <- parTraverse load deps