diff --git a/.github/workflows/format.yaml b/.github/workflows/format.yaml
deleted file mode 100644
index cc577ad..0000000
--- a/.github/workflows/format.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
-name: Check code formatting
-
-on:
-  pull_request:
-
-jobs:
-  build:
-    runs-on:
-      - ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v22
-      - run: nix develop --command fourmolu -m check .
diff --git a/.github/workflows/haskell.yml b/.github/workflows/haskell.yml
deleted file mode 100644
index 036416a..0000000
--- a/.github/workflows/haskell.yml
+++ /dev/null
@@ -1,81 +0,0 @@
-name: Haskell CI
-
-on:
-  push:
-    branches:
-      - main
-    tags:
-      - v*
-  pull_request:
-
-jobs:
-  build:
-    runs-on:
-      - ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Setup Haskell
-        id: setup-haskell
-        uses: haskell/actions/setup@v1
-        with:
-          ghc-version: '8.10.7'
-
-      - name: Cache
-        uses: actions/cache@v1
-        with:
-          path: ${{ steps.setup-haskell.outputs.cabal-store }}
-          key: ${{ runner.os }}-${{ github.sha }}
-          restore-keys: ${{ runner.os }}-
-
-      - name: Build dependencies
-        run: cabal build --only-dependencies
-
-      - name: Build
-        run: cabal build
-
-      - name: Test
-        run: cabal test
-
-      - name: Copy artifacts
-        run: |
-          mkdir ${{ github.workspace }}/build-artifacts
-          cabal install --install-method=copy --installdir=${{ github.workspace }}/build-artifacts
-
-      - name: Upload artifact
-        uses: actions/upload-artifact@v3
-        with:
-          name: build-artifact-${{ runner.os }}
-          path: ${{ github.workspace }}/build-artifacts
-          if-no-files-found: error
-
-  create-release:
-    if: startsWith(github.ref, 'refs/tags/')
-    needs: build
-    runs-on: ubuntu-latest
-
-    permissions:
-      contents: write
-
-    steps:
-      - name: Download build artifact
-        uses: actions/download-artifact@v3
-
-      - name: Create release
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          # Tag artifacts by os (only Linux for now)
-          mkdir release-artifacts
-          for path in build-artifact-Linux/*; do
-            name=${path##*/}
-            cp $path release-artifacts/$name-Linux
-          done
-
-          # Strip binaries
-          strip release-artifacts/*
-
-          gh release create ${{ github.ref_name }} \
-            --repo ${{ github.repository }} --draft --generate-notes \
-            release-artifacts/*
diff --git a/.github/workflows/nix.yml b/.github/workflows/nix.yml
index a66fd97..e12c257 100644
--- a/.github/workflows/nix.yml
+++ b/.github/workflows/nix.yml
@@ -7,6 +7,27 @@ on:
   pull_request:
 
 jobs:
+  format:
+    runs-on:
+      - ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@v4
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: DeterminateSystems/magic-nix-cache-action@v2
+
+      - uses: cachix/cachix-action@v12
+        with:
+           name: foliage
+           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - run: nix develop --accept-flake-config --command fourmolu -m check .
+
   build:
     runs-on:
       - ubuntu-latest
diff --git a/.github/workflows/update-flake-lock.yml b/.github/workflows/update-flake-lock.yml
index d51e30e..08f2905 100644
--- a/.github/workflows/update-flake-lock.yml
+++ b/.github/workflows/update-flake-lock.yml
@@ -11,11 +11,19 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v3
+
       - name: Install Nix
-        uses: cachix/install-nix-action@v19
+        uses: DeterminateSystems/nix-installer-action@v4
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: DeterminateSystems/magic-nix-cache-action@v2
+
+      - uses: cachix/cachix-action@v12
         with:
-          extra_nix_config: |
-            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+           name: foliage
+           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
       - name: Update flake.lock
         uses: DeterminateSystems/update-flake-lock@v16
         with:
@@ -23,5 +31,6 @@ jobs:
           pr-labels: |                  # Labels to be set on the PR
             dependencies
             automated
+
       - name: Print PR number
         run: echo Opened pull request ${{ steps.update.outputs.pull-request-number }}.