This project provides a Dockerized prerender service based on prerender with an in-memory cache. It is designed to render JavaScript-heavy pages (e.g., for SEO or bots) using headless Chromium.

• Headless Chromium rendering
• In-memory caching (prerender-memory-cache)
• Configurable cache TTL and size
• Lightweight Docker image (node:20-bullseye-slim)
• Ready to use with Docker Compose

├── Dockerfile

├── server.js

└── docker-compose.yml

docker build -t prerender-service .

or check GitHub repository

ghcr.io/justcoded/dockerize-prerender:latest

with tag latest or number tag.

Example docker-compose.yml for development:

services:
  webapp-prerender:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    shm_size: 1024mb
    restart: unless-stopped
    init: true
    environment:
      - PORT=3000
    # For qucker cahnges  
    volumes:
      - ./server.js:/app/server.js

or for prod/staging usage:

services:
  webapp-prerender:
    image: ghcr.io/justcoded/dockerize-prerender:latest
    shm_size: 1024mb
    restart: unless-stopped
    init: true
    environment:
      - PORT=3000
      # Maximum number of items to keep in the memory cache
      - CACHE_MAXSIZE=1000
      # Cache duration in seconds (43200s = 12 hours)
      - CACHE_TTL=43200
      # Wait time in ms after last network request before rendering
      - WAIT_AFTER_LAST_REQUEST=200
      

Run:

docker-compose up -d

The service runs a prerender server using headless Chromium. Incoming requests are rendered as fully loaded HTML pages. Responses are cached in memory using prerender-memory-cache. Cache settings are controlled via environment variables.

Uses system-installed Chromium (/usr/bin/chromium) Required dependencies are installed in the Docker image --no-sandbox is enabled for compatibility inside containers

SEO for SPA (React, Vue, Angular) Social media previews (Open Graph rendering) Rendering pages for bots/crawlers

Increase shm_size if Chromium crashes Tune CACHE_MAXSIZE based on memory limits Use a reverse proxy (e.g., Nginx) in production