How to Reduce Docker Image Size for a ReactJS Application from 1.43 GB to 22.4 MB

Docker image size significantly impacts CI/CD and cloud deployment, so reducing it is valuable. This guide demonstrates how to containerize a simple ReactJS app and shrink its image from 1.43 GB to as low as 22.4 MB using several techniques.

Step 1: Create the project – Use the Create React App scaffold:

npx create-react-app docker-image-test

Then install dependencies and start the app:

cd docker-image-test
yarn install
yarn start

Step 2: Build the first image – Add a Dockerfile:

FROM node:12
WORKDIR /app
COPY package.json ./
RUN yarn install
COPY . .
EXPOSE 3000
CMD ["yarn","start"]

Build and list the image:

docker build -t docker-image-test .
docker images

The resulting image is about 1.43 GB.

Step 3: Use a smaller base image – Replace node:12 with node:12-alpine , which reduces the size dramatically.

FROM node:12-alpine
WORKDIR /app
COPY package.json ./
RUN yarn install
COPY . .
EXPOSE 3000
CMD ["yarn","start"]

After rebuilding, the image shrinks to roughly 580 MB.

Step 4: Multi‑stage build – Separate the build and runtime stages so that only the compiled assets are included in the final image.

# STAGE 1
FROM node:12-alpine AS build
WORKDIR /app
COPY package.json ./
RUN yarn install
COPY . /app
RUN yarn build

# STAGE 2
FROM node:12-alpine
WORKDIR /app
RUN npm install -g webserver.local
COPY --from=build /app/build ./build
EXPOSE 3000
CMD webserver.local -d ./build

This reduces the image to about 97.5 MB.

Step 5: Serve with Nginx – Use an Nginx static server for the built assets, further cutting the image size.

# STAGE 1
FROM node:12-alpine AS build
WORKDIR /app
COPY package.json ./
RUN yarn install
COPY . /app
RUN yarn build

# STAGE 2
FROM nginx:stable-alpine
COPY --from=build /app/build /usr/share/nginx/html
EXPOSE 80
CMD ["nginx","-g","daemon off;"]

The final image is only 22.4 MB and runs the React app efficiently.

These techniques—using Alpine base images, multi‑stage builds, and a lightweight web server—can be applied to any Node.js project to achieve much smaller, more portable Docker containers.