Is this Dockerfile generator free?

Yes. SyntaxSnap's Dockerfile Generator is completely free with no accounts, no ads, and no usage limits.

Does my code leave the browser?

No. All Dockerfile generation happens 100% client-side in your browser. No data is transmitted to any server.

Which frameworks are supported?

Node.js, Next.js (with standalone mode), and Astro. The generator supports npm, yarn, pnpm, and bun package managers with Node 18, 20, and 22 alpine base images.

Does it follow Docker security best practices?

Yes. Generated Dockerfiles use multi-stage builds, non-root users, minimal alpine base images, and health checks to follow container security best practices.

Dockerfile Generator

Create production-ready, highly optimized multi-stage Dockerfiles and .dockerignore files for your JavaScript frameworks instantly.

Configuration

Framework

Package Manager

Node.js Version

# Optimized Multi-stage Dockerfile for Next.js (Standalone)
FROM node:22-alpine AS base
RUN npm install -g pnpm

# Step 1. Rebuild the source code only when needed
FROM base AS builder
WORKDIR /app
COPY package.json pnpm-lock.yaml ./
RUN pnpm install --frozen-lockfile
COPY . .
# Next.js telemetry disable
ENV NEXT_TELEMETRY_DISABLED=1
RUN pnpm run build

# Step 2. Production image, copy all the files and run next
FROM node:22-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED=1

RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs

# Set the correct permission for prerender cache
RUN mkdir .next
RUN chown nextjs:nodejs .next

# Automatically leverage output traces to reduce image size
# https://nextjs.org/docs/advanced-features/output-file-tracing
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
COPY --from=builder --chown=nextjs:nodejs /app/public ./public

USER nextjs
EXPOSE 3000
ENV PORT=3000
ENV HOSTNAME="0.0.0.0"

HEALTHCHECK --interval=30s --timeout=3s --start-period=5s \
  CMD wget --no-verbose --tries=1 --spider http://localhost:3000/ || exit 1

CMD ["node", "server.js"]

Why Multi-Stage Builds?

A standard Dockerfile copies all your source code and development dependencies into the final image, resulting in bloated sizes (often 1GB+) and increased security vulnerabilities.

Multi-stage builds solve this by using separate environments: one for installing dependencies and building the application (the builder stage), and a completely fresh, lightweight image that only receives the compiled artifacts (the runner stage). This often reduces the final image size to under 150MB.

Best Practices Included

Alpine Uses node:alpine base images by default for the smallest possible OS footprint.
Standalone Next.js configurations automatically utilize the standalone output trace to drastically reduce container size.
Security Runs the application as a non-root node user to prevent privilege escalation attacks.
Ignore Generates a strict .dockerignore to prevent secrets (.env) and local modules from leaking into the build context.