API Service README Template

Documenting an API Service

An API service README needs to communicate how to set up, run, and interact with the API. Developers reading it may be backend contributors, frontend developers consuming the API, or DevOps engineers deploying it.

Authentication Section

Document the authentication method upfront:

# Obtain a token
curl -X POST https://api.example.com/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email": "user@example.com", "password": "secret"}'

# Use the token
curl https://api.example.com/v1/items \
  -H "Authorization: Bearer eyJhbG..."

Endpoint Documentation Table

A concise endpoint table gives an overview of the entire API:

Method	Endpoint	Description	Auth
POST	/auth/login	Authenticate user	No
GET	/v1/items	List all items	Yes
POST	/v1/items	Create an item	Yes
GET	/v1/items/:id	Get item by ID	Yes
PUT	/v1/items/:id	Update an item	Yes
DELETE	/v1/items/:id	Delete an item	Yes

Request/Response Examples

For each major endpoint, show a complete request and response:

# Create an item
curl -X POST https://api.example.com/v1/items \
  -H "Authorization: Bearer TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name": "Widget", "price": 29.99}'

Response:

{
  "id": "abc123",
  "name": "Widget",
  "price": 29.99,
  "createdAt": "2024-01-15T10:30:00Z"
}

Error Codes

Document common error responses:

Code	Description
400	Invalid request body
401	Missing or invalid token
403	Insufficient permissions
404	Resource not found
429	Rate limit exceeded

Docker Deployment

Most API services benefit from Docker documentation:

docker build -t my-api .
docker run -p 3000:3000 --env-file .env my-api