diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 2021 The Haskell IDE team
+
+   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.
diff --git a/hls-floskell-plugin.cabal b/hls-floskell-plugin.cabal
new file mode 100644
--- /dev/null
+++ b/hls-floskell-plugin.cabal
@@ -0,0 +1,43 @@
+cabal-version:      2.4
+name:               hls-floskell-plugin
+version:            1.0.0.0
+synopsis:           Integration with the Floskell code formatter
+description:
+  Please see the README on GitHub at <https://github.com/haskell/haskell-language-server#readme>
+
+license:            Apache-2.0
+license-file:       LICENSE
+author:             The Haskell IDE Team
+copyright:          The Haskell IDE Team
+maintainer:         alan.zimm@gmail.com
+category:           Development
+build-type:         Simple
+extra-source-files:
+  LICENSE
+  test/testdata/**/*.hs
+
+library
+  exposed-modules:  Ide.Plugin.Floskell
+  hs-source-dirs:   src
+  build-depends:
+    , base            >=4.12     && <5
+    , floskell       ^>=0.10
+    , ghcide           >=1.2 && <1.4
+    , hls-plugin-api  ^>=1.1
+    , lsp-types
+    , text
+    , transformers
+
+  default-language: Haskell2010
+
+test-suite tests
+  type:             exitcode-stdio-1.0
+  default-language: Haskell2010
+  hs-source-dirs:   test
+  main-is:          Main.hs
+  ghc-options:      -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+    , base
+    , hls-floskell-plugin
+    , hls-test-utils       ^>=1.0
+    , text
diff --git a/src/Ide/Plugin/Floskell.hs b/src/Ide/Plugin/Floskell.hs
new file mode 100644
--- /dev/null
+++ b/src/Ide/Plugin/Floskell.hs
@@ -0,0 +1,58 @@
+{-# LANGUAGE OverloadedStrings   #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Ide.Plugin.Floskell
+  (
+    descriptor
+  , provider
+  )
+where
+
+import           Control.Monad.IO.Class
+import qualified Data.Text               as T
+import qualified Data.Text.Lazy          as TL
+import qualified Data.Text.Lazy.Encoding as TL
+import           Development.IDE         as D hiding (pluginHandlers)
+import           Floskell
+import           Ide.PluginUtils
+import           Ide.Types
+import           Language.LSP.Types
+
+-- ---------------------------------------------------------------------
+
+descriptor :: PluginId -> PluginDescriptor IdeState
+descriptor plId = (defaultPluginDescriptor plId)
+  { pluginHandlers = mkFormattingHandlers provider
+  }
+
+-- ---------------------------------------------------------------------
+
+-- | Format provider of Floskell.
+-- Formats the given source in either a given Range or the whole Document.
+-- If the provider fails an error is returned that can be displayed to the user.
+provider :: FormattingHandler IdeState
+provider _ideState typ contents fp _ = liftIO $ do
+    let file = fromNormalizedFilePath fp
+    config <- findConfigOrDefault file
+    let (range, selectedContents) = case typ of
+          FormatText    -> (fullRange contents, contents)
+          FormatRange r -> (r, extractRange r contents)
+        result = reformat config (Just file) (TL.encodeUtf8 (TL.fromStrict selectedContents))
+    case result of
+      Left  err -> return $ Left $ responseError (T.pack $  "floskellCmd: " ++ err)
+      Right new -> return $ Right $ List [TextEdit range . TL.toStrict $ TL.decodeUtf8 new]
+
+-- | Find Floskell Config, user and system wide or provides a default style.
+-- Every directory of the filepath will be searched to find a user configuration.
+-- Also looks into places such as XDG_CONFIG_DIRECTORY<https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html>.
+-- This function may not throw an exception and returns a default config.
+findConfigOrDefault :: FilePath -> IO AppConfig
+findConfigOrDefault file = do
+  mbConf <- findAppConfigIn file
+  case mbConf of
+    Just confFile -> readAppConfig confFile
+    Nothing ->
+      let gibiansky = head (filter (\s -> styleName s == "gibiansky") styles)
+      in return $ defaultAppConfig { appStyle = gibiansky }
+
+-- ---------------------------------------------------------------------
diff --git a/test/Main.hs b/test/Main.hs
new file mode 100644
--- /dev/null
+++ b/test/Main.hs
@@ -0,0 +1,27 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Main(main) where
+
+import qualified Data.Text.Lazy          as TL
+import qualified Data.Text.Lazy.Encoding as TL
+import qualified Ide.Plugin.Floskell     as Floskell
+import           Test.Hls
+
+main :: IO ()
+main = defaultTestRunner tests
+
+plugin :: PluginDescriptor IdeState
+plugin = Floskell.descriptor "floskell"
+
+tests :: TestTree
+tests = testGroup "floskell"
+  [ goldenGitDiff "formats a document" "test/testdata/Floskell.formatted_document.hs" $ runSessionWithServerFormatter plugin "floskell" "test/testdata" $ do
+        doc <- openDoc "Floskell.hs" "haskell"
+        formatDoc doc (FormattingOptions 4 True Nothing Nothing Nothing)
+        TL.encodeUtf8 . TL.fromStrict <$> documentContents doc
+
+  , goldenGitDiff "formats a range" "test/testdata/Floskell.formatted_range.hs" $ runSessionWithServerFormatter plugin "floskell" "test/testdata" $ do
+      doc <- openDoc "Floskell.hs" "haskell"
+      let range = Range (Position 1 0) (Position 4 22)
+      formatRange doc (FormattingOptions 4 True Nothing Nothing Nothing) range
+      TL.encodeUtf8 . TL.fromStrict <$> documentContents doc
+  ]
diff --git a/test/testdata/Floskell.formatted_document.hs b/test/testdata/Floskell.formatted_document.hs
new file mode 100644
--- /dev/null
+++ b/test/testdata/Floskell.formatted_document.hs
@@ -0,0 +1,17 @@
+module Floskell where
+
+import           Data.List
+import           Prelude
+import           Data.Int
+
+foo :: Int -> Int
+foo 3 = 2
+foo x = x
+
+bar :: String -> IO String
+bar s = do
+  x <- return "hello"
+  return "asdf"
+
+data Baz = Baz { a :: Int, b :: String }
+
diff --git a/test/testdata/Floskell.formatted_range.hs b/test/testdata/Floskell.formatted_range.hs
new file mode 100644
--- /dev/null
+++ b/test/testdata/Floskell.formatted_range.hs
@@ -0,0 +1,14 @@
+module    Floskell where
+import           Data.List
+import           Prelude
+import           Data.Int
+foo   :: Int ->  Int
+foo  3 = 2
+foo    x  = x
+bar   :: String ->   IO String
+bar s =  do
+      x <- return "hello"
+      return "asdf"
+
+data Baz = Baz { a :: Int, b :: String }
+
diff --git a/test/testdata/Floskell.hs b/test/testdata/Floskell.hs
new file mode 100644
--- /dev/null
+++ b/test/testdata/Floskell.hs
@@ -0,0 +1,15 @@
+module    Floskell where
+import Data.List
+
+import Prelude
+import Data.Int
+foo   :: Int ->  Int
+foo  3 = 2
+foo    x  = x
+bar   :: String ->   IO String
+bar s =  do
+      x <- return "hello"
+      return "asdf"
+
+data Baz = Baz { a :: Int, b :: String }
+
