diff --git a/.env.example b/.env.example
index f774500..23e8941 100644
--- a/.env.example
+++ b/.env.example
@@ -1,3 +1,7 @@
+# === Server Port ===
+# Port the Next.js server listens on (dev and production)
+# PORT=3000
+
 # === Authentication ===
 # Admin user seeded on first run (only if no users exist in DB)
 AUTH_USER=admin
diff --git a/Dockerfile b/Dockerfile
index b8915af..792ef4a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -32,9 +32,9 @@ COPY --from=build /app/src/lib/schema.sql ./src/lib/schema.sql
 RUN mkdir -p .data && chown nextjs:nodejs .data
 RUN apt-get update && apt-get install -y curl --no-install-recommends && rm -rf /var/lib/apt/lists/*
 USER nextjs
-EXPOSE 3000
 ENV PORT=3000
+EXPOSE 3000
 ENV HOSTNAME=0.0.0.0
 HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
-  CMD curl -f http://localhost:3000/login || exit 1
+  CMD curl -f http://localhost:${PORT:-3000}/login || exit 1
 CMD ["node", "server.js"]
diff --git a/docker-compose.yml b/docker-compose.yml
index 9a16156..7ae529a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -3,7 +3,9 @@ services:
     build: .
     container_name: mission-control
     ports:
-      - "${MC_PORT:-3000}:3000"
+      - "${MC_PORT:-3000}:${PORT:-3000}"
+    environment:
+      - PORT=${PORT:-3000}
     env_file:
       - path: .env
         required: false
diff --git a/package.json b/package.json
index 25e8136..91ec7a0 100644
--- a/package.json
+++ b/package.json
@@ -3,9 +3,9 @@
   "version": "1.3.0",
   "description": "OpenClaw Mission Control — open-source agent orchestration dashboard",
   "scripts": {
-    "dev": "next dev --hostname 127.0.0.1",
+    "dev": "next dev --hostname 127.0.0.1 --port ${PORT:-3000}",
     "build": "next build",
-    "start": "next start --hostname 0.0.0.0 --port 3005",
+    "start": "next start --hostname 0.0.0.0 --port ${PORT:-3000}",
     "lint": "eslint .",
     "typecheck": "tsc --noEmit",
     "test": "vitest run",