diff --git a/.env.dev.example b/.env.dev.example
new file mode 100644
index 00000000..4ab88223
--- /dev/null
+++ b/.env.dev.example
@@ -0,0 +1,49 @@
+# Bulwark Webmail — Development Configuration
+# Copy this file to .env.local to run with the built-in mock JMAP server.
+# No external mail server required — great for UI development and testing.
+#
+# Usage:
+#   cp .env.dev.example .env.local
+#   npm run dev
+#   Open http://localhost:3000 — log in with any username/password.
+
+# =============================================================================
+# Mock JMAP Server
+# =============================================================================
+
+# Enable the built-in mock JMAP server (served at /api/dev-jmap)
+DEV_MOCK_JMAP=true
+
+# Point the app at its own mock endpoint.
+# IMPORTANT: This must match the origin the app runs on (default: port 3000).
+# Using a different port (e.g. 3001) will cause CORS errors.
+JMAP_SERVER_URL=/api/dev-jmap
+
+# =============================================================================
+# App
+# =============================================================================
+
+APP_NAME=Bulwark Webmail (Dev)
+
+# =============================================================================
+# Session & Settings Sync (optional for dev)
+# =============================================================================
+
+SESSION_SECRET=dev-secret-not-for-production
+SETTINGS_SYNC_ENABLED=true
+
+# =============================================================================
+# Logging (verbose for development)
+# =============================================================================
+
+LOG_FORMAT=text
+LOG_LEVEL=debug
+
+# =============================================================================
+# Login Page Customization (optional)
+# =============================================================================
+
+# LOGIN_COMPANY_NAME=Dev Team
+# LOGIN_IMPRINT_URL=https://example.com/imprint
+# LOGIN_PRIVACY_POLICY_URL=https://example.com/privacy
+# LOGIN_WEBSITE_URL=https://example.com
diff --git a/.gitignore b/.gitignore
index fd6cd363..22336596 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,6 +33,7 @@ yarn-error.log*
 # env files
 .env*
 !.env.example
+!.env.dev.example
 
 # vercel
 .vercel