diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
new file mode 100644
index 000000000..f8d958a29
--- /dev/null
+++ b/.github/workflows/macos.yml
@@ -0,0 +1,84 @@
+name: macos
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - kb/nix-dev
+
+jobs:
+  frontend_dev_macos:
+    name: frontend-dev on macOS
+    runs-on: macos-latest
+    timeout-minutes: 60
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v25
+        with:
+          install_url: https://releases.nixos.org/nix/nix-2.31.2/install
+
+      - name: Configure Cachix
+        uses: cachix/cachix-action@v14
+        with:
+          name: catcolab-jmoggr
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: Run frontend-dev and verify Vite serves content
+        run: |
+          set -euo pipefail
+          mkdir -p /tmp/frontend-dev-logs
+
+          # Launch frontend-dev in the background. The script ends with
+          # `exec pnpm exec vite --host`, so the launched PID becomes vite
+          # once setup finishes.
+          nix run .#frontend-dev -- --port 5173 \
+            > /tmp/frontend-dev-logs/stdout.log \
+            2> /tmp/frontend-dev-logs/stderr.log &
+          DEV_PID=$!
+
+          cleanup() {
+            echo "--- stdout ---"
+            cat /tmp/frontend-dev-logs/stdout.log || true
+            echo "--- stderr ---"
+            cat /tmp/frontend-dev-logs/stderr.log || true
+            # Try killing the whole process group, then the PID directly.
+            kill -TERM -"$DEV_PID" 2>/dev/null || kill -TERM "$DEV_PID" 2>/dev/null || true
+            sleep 2
+            kill -KILL -"$DEV_PID" 2>/dev/null || kill -KILL "$DEV_PID" 2>/dev/null || true
+          }
+          trap cleanup EXIT
+
+          # Generous timeout: cold Nix evaluation on macOS may build
+          # catlog-wasm-browser, document-types-wasm, and catcolabApi from
+          # source if Cachix lacks aarch64-darwin artifacts.
+          deadline=$(( $(date +%s) + 3500 ))
+          until curl -fsS --max-time 5 http://localhost:5173/ > /dev/null; do
+            if [ "$(date +%s)" -ge "$deadline" ]; then
+              echo "Timed out waiting for Vite dev server" >&2
+              exit 1
+            fi
+            if ! kill -0 "$DEV_PID" 2>/dev/null; then
+              echo "frontend-dev process exited prematurely" >&2
+              exit 1
+            fi
+            sleep 5
+          done
+
+          echo "Vite dev server is responding."
+
+          # Confirm Vite is actually serving an HTML page, not a placeholder.
+          if ! curl -fsS http://localhost:5173/ | grep -qi '<html'; then
+            echo "Response did not look like an HTML page" >&2
+            exit 1
+          fi
+
+      - name: Upload dev server logs
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: frontend-dev-logs-macos
+          path: /tmp/frontend-dev-logs
diff --git a/flake.nix b/flake.nix
index 1619af6b4..6f8a859c2 100644
--- a/flake.nix
+++ b/flake.nix
@@ -246,6 +246,7 @@
               document-types-wasm = pkgs.callPackage ./packages/document-types/default.nix craneArgs;
               frontend = frontendPackage.package;
               frontend-tests = frontendPackage.tests;
+              frontend-dev = frontendPackage.dev;
             };
 
           linuxOnlyPackages = {
diff --git a/package.json b/package.json
index f0853878b..60f68743a 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "scripts": {
         "test": "echo \"Error: no test specified\" && exit 1",
         "build:deps": "pnpm --filter ./packages/frontend run build:deps",
-        "dev": "pnpm --filter ./packages/frontend run dev"
+        "dev": "nix run .#frontend-dev -- "
     },
     "devDependencies": {
         "depcheck": "^1.4.7",
diff --git a/packages/frontend/default.nix b/packages/frontend/default.nix
index 21d0fafaa..a81a32959 100644
--- a/packages/frontend/default.nix
+++ b/packages/frontend/default.nix
@@ -265,7 +265,48 @@ let
       meta.mainProgram = "${name}-tests";
     }
   );
+
+  # `nix run .#frontend-dev` from the repository root: this drops the Nix-built
+  # wasm/API artifacts into the source tree and then launches `vite --host`
+  # against a regular pnpm install. 
+  dev = pkgs.writeShellApplication {
+    name = "frontend-dev";
+    runtimeInputs = with pkgs; [
+      nodejs_24
+      pnpm
+    ];
+    text = ''
+      if [ ! -f flake.nix ]; then
+        echo "Error: must be run from the repository root" >&2
+        exit 1
+      fi
+
+      echo "Setting up Nix-built dependencies..."
+
+      mkdir -p packages/catlog-wasm/dist/pkg-browser
+      rm -rf packages/catlog-wasm/dist/pkg-browser/*
+      cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.catlog-wasm-browser}/* packages/catlog-wasm/dist/pkg-browser/
+
+      mkdir -p packages/document-types/pkg
+      rm -rf packages/document-types/pkg/*
+      cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.document-types-wasm}/* packages/document-types/pkg/
+
+      mkdir -p packages/backend/pkg/src
+      rm -rf packages/backend/pkg/src/*
+      cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.catcolabApi}/src packages/backend/pkg/
+
+      echo "Installing npm dependencies..."
+      pnpm install
+
+      cd packages/frontend
+      echo "Generating CSS module types..."
+      pnpm run build:tcm
+
+      echo "Starting Vite dev server..."
+      exec pnpm exec vite --host "$@"
+    '';
+  };
 in
 {
-  inherit package tests;
+  inherit package tests dev;
 }