How I Reduced My Next.js Docker Image from 4.1 GB to 230 MB

As developers, we’re constantly looking for ways to make our applications faster, smaller, and easier to deploy. Recently, I discovered just how much bloat was hiding in my Docker image—and how simple it was to eliminate it with a few smart changes.

📦 The Starting Point

I’m working on a full-stack Next.js project, containerized for deployment. My original Docker image, built using npm and a fairly typical Dockerfile, weighed in at a whopping 4.1 GB.

That’s fine during development, but once you’re pushing and pulling this image in CI/CD, across environments, or to a production registry—it quickly becomes a bottleneck.

⚡️ Step 1: Switching from npm to pnpm

The first change I made was switching from npm to pnpm. It uses a global content-addressable store and symlinks, meaning:

No duplicated dependencies
Smaller node_modules
Faster install times

Commands used:

npm install -g pnpm
rm -rf node_modules package-lock.json
pnpm install

This change alone reduced the image size from 4.1 GB to 1.6 GB.

🛠 Step 2: Enabling Standalone Output in Next.js

While discussing optimization strategies on Reddit, someone suggested enabling Next.js standalone output — and this was a game changer.

Add this to your config:

jsCopyEdit// next.config.js module.exports = { output: 'standalone', };

Next.js then generates a minimal .next/standalone directory during the build, containing:

The compiled app
Only the production-required dependencies

This removes the need to include the entire source or full node_modules in the final image.

🐳 Step 3: Optimizing the Dockerfile

Here’s the optimized Dockerfile:

# Use minimal Node image 
FROM node:18-alpine AS base 
WORKDIR /app 

# Install pnpm 
RUN npm install -g pnpm 

# Install deps and build 
FROM base AS builder 
COPY . . 
RUN pnpm install --frozen-lockfile 
RUN pnpm build 

# Final image 
FROM node:18-alpine AS runner WORKDIR /app 

# Copy standalone build output 
COPY --from=builder /app/.next/standalone ./ 
COPY --from=builder /app/public ./public 

EXPOSE 3000 
CMD ["node", "server.js"]