diff --git a/.github/workflows/draw-keymaps.yml b/.github/workflows/draw-keymaps.yml
index aa03e4c..7c74b3d 100644
--- a/.github/workflows/draw-keymaps.yml
+++ b/.github/workflows/draw-keymaps.yml
@@ -4,12 +4,8 @@ on:
   push:               # automatically run on changes to following paths
     paths:
       - "**.lock"
+      - "drawer/**"
       - "config/**"
-env:
-  km_dr_version: main
-  km_dr_config: config/keymap_drawer.yaml
-  keymap_path: config/*.keymap
-  output_folder: img
 
 jobs:
   draw:
@@ -21,75 +17,24 @@ jobs:
     steps:
 
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
-          fetch-depth: 1 # Set to 2 if amending, or 1 if creating a new commit
+          # Set to 2 if amending, or 1 if creating a new commit
+          fetch-depth: 1
           submodules: recursive
 
-      - name: Install python dependencies
-        run: |
-          pip install "git+https://github.com/caksoylar/keymap-drawer.git@${{ env.km_dr_version }}"
-          pip install pyyaml
+      - name: Install nix
+        uses: cachix/install-nix-action@v25
+      - name: Setup nix cache
+        uses: DeterminateSystems/magic-nix-cache-action@main
 
-      # TODO get keyboads & configs dynamically
-      - name: Parse keymap
-        run: |
-          # TODO set generic vars in one place globally
-          CONFIG="${{ env.km_dr_config }}"
-
-          for KEYMAP in ${{ env.keymap_path }}; do
-            KEYBOARD=$(basename -s .keymap "$KEYMAP")
-            OUTPUT="${{ env.output_folder }}/${KEYBOARD}.yaml"
-
-            # TODO consider running through `parallel`?
-            echo "Parsing keymap for $KEYBOARD"
-            keymap -c "$CONFIG" parse -z "$KEYMAP" > "$OUTPUT"
-          done
-
-      - name: Draw keymap for all layers
-        run: |
-          CONFIG="${{ env.km_dr_config }}"
-
-          # FIXME can glob false positeves, e.g. previous keymaps
-          for KEYMAP in ${{ env.output_folder }}/*.yaml; do
-            KEYBOARD=$(basename -s .yaml "$KEYMAP")
-            OUTPUT="${{ env.output_folder }}/${KEYBOARD}.svg"
-
-            echo "Drawing all layers for $KEYBOARD"
-            keymap -c "$CONFIG" draw "$KEYMAP" > "$OUTPUT"
-          done
-
-
-      - name: Draw seperate layer keymaps
-        run: |
-          # Ensure errors propagate when piping stdout
-          set -o pipefail
-
-          export CONFIG="${{ env.km_dr_config }}"
-
-          # Function to draw the given layer's keymap
-          draw() {
-            KEYMAP="$1"
-            LAYER="$2"
-            KEYBOARD=$(basename -s .yaml "$KEYMAP")
-            OUTPUT="${{ env.output_folder }}/${KEYBOARD}_${LAYER}.svg"
-
-            echo "Drawing $LAYER layer for $KEYBOARD"
-            keymap -c "$CONFIG" draw "$KEYMAP" -s "$LAYER" > "$OUTPUT"
-          }
-          export -f draw # Ensure the draw function can be called by `parallel`'s subprocess
-
-          # FIXME can glob false positeves, e.g. previous keymaps
-          for KEYMAP in ${{ env.output_folder }}/*.yaml; do
-            # Run `draw()` for each layer in the keymap. Up to 4 layers at a time...
-            echo "Drawing layers in parallel"
-            python3 .github/workflows/layers.py "$KEYMAP" \
-            | parallel --jobs 4 draw "$KEYMAP"
-          done
+      - name: Draw keymaps
+        run: nix run . -- draw
 
+      # TODO print to $GITHUB_STEP_SUMMARY
       - name: Commit changes
         uses: stefanzweifel/git-auto-commit-action@v4
         with:
           commit_message: "[Draw] ${{ github.event.head_commit.message || '(Manually triggered)' }}"
-          file_pattern: ${{ env.output_folder }}/*.svg ${{ env.output_folder }}/*.yaml
+          file_pattern: img/**
 
diff --git a/.github/workflows/layers.py b/.github/workflows/layers.py
deleted file mode 100644
index 8efc8fc..0000000
--- a/.github/workflows/layers.py
+++ /dev/null
@@ -1,16 +0,0 @@
-from sys import argv
-import yaml
-
-if len(argv) < 2:
-    print(f'Usage: python {argv[0]} FILINAME')
-    exit(1)
-
-FILINAME = argv[1]
-
-with open(FILINAME, 'r') as file:
-    doc = yaml.safe_load(file)
-    if not 'layers' in doc:
-        print('Invalid file')
-        exit(2)
-    for layer in doc['layers'].keys():
-        print(layer)
diff --git a/drawer/default.nix b/drawer/default.nix
index d0889ec..c65b70a 100644
--- a/drawer/default.nix
+++ b/drawer/default.nix
@@ -5,11 +5,15 @@
 }: let
 in {
     perSystem = {
+      config,
       pkgs,
       system,
       ...
     }: let
       inherit (inputs.poetry2nix.lib.mkPoetry2Nix {inherit pkgs;}) mkPoetryApplication;
+
+      exe = lib.getExe config.packages.keymap-drawer;
+      yq = lib.getExe pkgs.yq-go;
     in {
       packages = {
         keymap-drawer = mkPoetryApplication {
@@ -21,4 +25,42 @@ in {
           };
         };
     };
+
+      devshells.default.commands = [
+        {
+          name = "draw";
+          command = /*bash*/ ''
+            set +e
+
+            out="$PRJ_ROOT"/img
+            keymap_dir="$PRJ_ROOT"/config
+            cmd="${exe} --config $keymap_dir/keymap_drawer.yaml"
+
+            echo "Removing previous images"
+            rm "$out"/*
+
+            for file in "$keymap_dir"/*.keymap
+            do
+              name="$(basename --suffix=".keymap" "$file")"
+              config="$out/$name.yaml"
+              echo "Found $name keymap"
+
+              echo "- Parsing keymap-drawer"
+              $cmd  parse --zmk-keymap "$file" > "$config"
+
+              echo "- Drawing all layers"
+              $cmd draw "$config" > "$out"/"$name".svg
+
+              layers=$(${yq} '.layers | keys | .[]' "$config")
+              for layer in $layers
+              do
+                echo "- Drawing $layer layer"
+                $cmd draw "$config" --select-layers "$layer" > "$out"/"$name"_"$layer".svg
+              done
+            done
+          '';
+          help = "Draw SVG images of the keymap";
+        }
+      ];
+  };
 }