Comprehensive guide for contributing to and working with freeCodeCamp's open-source codebase and curriculum platform
Skill by ara.so — Daily 2026 Skills collection.
freeCodeCamp.org is a free, open-source learning platform with thousands of interactive coding challenges, certifications, and a full-stack curriculum. The codebase includes a React/TypeScript frontend, Node.js/Fastify backend, and a YAML/Markdown-based curriculum system.
freeCodeCamp/
├── api/ # Fastify API server (TypeScript)
├── client/ # Gatsby/React frontend (TypeScript)
├── curriculum/ # All challenges and certifications (YAML/Markdown)
│ └── challenges/
│ ├── english/
│ │ ├── responsive-web-design/
│ │ ├── javascript-algorithms-and-data-structures/
│ │ └── ...
│ └── ...
├── tools/
│ ├── challenge-helper-scripts/ # CLI tools for curriculum authoring
│ └── ui-components/ # Shared React components
├── config/ # Shared configuration
└── e2e/ # Playwright end-to-end tests
nvm or fnm)git clone https://github.com/<YOUR_USERNAME>/freeCodeCamp.git
cd freeCodeCamp
pnpm install
cp sample.env .env
Key .env variables to set:
# MongoDB
MONGOHQ_URL=mongodb://127.0.0.1:27017/freecodecamp
# GitHub OAuth (create at github.com/settings/developers)
GITHUB_ID=$GITHUB_OAUTH_CLIENT_ID
GITHUB_SECRET=$GITHUB_OAUTH_CLIENT_SECRET
# Auth
JWT_SECRET=$YOUR_JWT_SECRET
SESSION_SECRET=$YOUR_SESSION_SECRET
# Email (optional for local dev)
SENDGRID_API_KEY=$SENDGRID_API_KEY
pnpm run seed
# Start everything (API + Client)
pnpm run develop
# Or start individually:
pnpm run develop:api # Fastify API on :3000
pnpm run develop:client # Gatsby on :8000
Challenges are stored as YAML/Markdown files under curriculum/challenges/.
# curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/comment-your-javascript-code.md
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