diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 00000000..ce656d9b
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,81 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: haskell-actions/setup@v2
+        with:
+          ghc-version: "9.8.2"
+          cabal-version: "3.12.1.0"
+
+      - run: |
+          cabal update
+          cabal build all
+
+  tests:
+    name: Tests
+    runs-on: ubuntu-latest
+    needs: build
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: haskell-actions/setup@v2
+        with:
+          ghc-version: "9.8.2"
+          cabal-version: "3.12.1.0"
+
+      - run: |
+          cabal update
+          cabal test all
+
+  format-hs:
+    name: Haskell format
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: haskell-actions/setup@v2
+        with:
+          ghc-version: "9.8.2"
+          cabal-version: "3.12.1.0"
+
+      - name: Install ormolu
+        run: |
+          cabal install ormolu --overwrite-policy=always
+          echo "$HOME/.cabal/bin" >> "$GITHUB_PATH"
+
+      - name: Check formatting
+        run: |
+          find . \
+            -name '*.hs' \
+            -not -path './dist-newstyle/*' \
+            -not -path './runtimes/*' \
+            -exec ormolu --mode check {} +
+
+  prettier:
+    name: Prettier
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+
+      - run: npm install --global prettier
+
+      - run: prettier --check . --ignore-path .prettierignore
diff --git a/cli/CLI/UI.hs b/cli/CLI/UI.hs
index 915bb055..8820341a 100644
--- a/cli/CLI/UI.hs
+++ b/cli/CLI/UI.hs
@@ -4,23 +4,23 @@
 
 module CLI.UI where
 
+import CLI.AppEnv (ConfigLoadResult (clrWarning))
 import Control.Concurrent (forkIO, threadDelay)
 import Control.Concurrent.MVar (MVar, newMVar, withMVar)
 import Control.Exception (SomeException, displayException, try)
 import Control.Monad (unless, when)
 import Data.Bits ((.|.))
 import Data.Char (toLower)
+import Data.Foldable (for_)
 import Data.IORef (IORef, atomicModifyIORef', modifyIORef', newIORef, readIORef, writeIORef)
 import Data.List (isInfixOf)
 import Data.Maybe (isNothing)
-import Data.Foldable (for_)
 import Data.Text (Text)
 import Data.Text qualified as T
 import Data.Text.IO qualified as TIO
 import System.Environment (lookupEnv)
-import System.Info (os)
 import System.IO (Handle, hFlush, hIsTerminalDevice, stdin, stdout)
-import CLI.AppEnv (ConfigLoadResult (clrWarning))
+import System.Info (os)
 #if defined(mingw32_HOST_OS)
 import System.Win32.Console (eNABLE_PROCESSED_OUTPUT, eNABLE_VIRTUAL_TERMINAL_PROCESSING, getConsoleMode, setConsoleMode)
 import System.Win32.Types (withHandleToHANDLE)
diff --git a/cli/Main.hs b/cli/Main.hs
index 8d4b8d26..2df15e5e 100644
--- a/cli/Main.hs
+++ b/cli/Main.hs
@@ -3,20 +3,18 @@
 module Main where
 
 import CLI.Commands
-import CLI.Runtime (Runtime, mkRuntime)
 import CLI.Config qualified as Config
 import CLI.Download qualified as Download
 import CLI.Onboarding (runOnboarding)
+import CLI.Runtime (Runtime, mkRuntime)
 import CLI.Submit qualified as Submit
 import Control.Exception (SomeException, try)
-import Data.List (find)
 import Data.Version (showVersion)
 import GHC.IO.Encoding (utf8)
 import Options.Applicative
 import Options.Applicative.Help.Pretty (Doc, pretty, vsep)
 import Paths_openleetcode qualified
-import System.Environment (getArgs, withArgs)
-import System.Exit (exitWith, ExitCode (ExitFailure, ExitSuccess))
+import System.Exit (ExitCode (ExitFailure, ExitSuccess), exitWith)
 import System.IO (hSetEncoding, stderr, stdout)
 #if defined(mingw32_HOST_OS)
 import System.Win32.Console (setConsoleOutputCP)
@@ -70,11 +68,16 @@ cliHelpFooter =
 
 initConsoleEncoding :: IO ()
 initConsoleEncoding = do
-#if defined(mingw32_HOST_OS) 
-  do
-    _ <- try (setConsoleOutputCP 65001) :: IO (Either SomeException ())
-    pure ()
-#endif
+  setupWindowsCP
   _ <- try (hSetEncoding stdout utf8) :: IO (Either SomeException ())
   _ <- try (hSetEncoding stderr utf8) :: IO (Either SomeException ())
   pure ()
+
+setupWindowsCP :: IO ()
+#if defined(mingw32_HOST_OS)
+setupWindowsCP = do
+  _ <- try (setConsoleOutputCP 65001) :: IO (Either SomeException ())
+  pure ()
+#else
+setupWindowsCP = pure ()
+#endif