The Core Idea

REST (Representational State Transfer) is an architectural style, not a protocol. It defines six constraints that make distributed systems predictable and scalable. The most critical: statelessness. Every request must carry all the information needed to process it. The server stores no session state between requests.

HTTP Verbs Map to Actions

REST uses HTTP methods to express intent:

• GET — read a resource, safe and idempotent
• POST — create a new resource
• PUT — replace a resource entirely
• PATCH — partial update
• DELETE — remove a resource

Idempotency matters: calling DELETE /users/42 ten times has the same effect as calling it once. POST is not idempotent — each call may create a new resource.

Resource Naming Rules

Use nouns, not verbs. Collections are plural:

# Good
GET  /articles
GET  /articles/99
POST /articles

# Bad
GET /getArticles
GET /fetchArticleById?id=99

Nest resources only one level deep. /users/5/orders is fine. /users/5/orders/3/items/7/reviews is a maintenance nightmare. Flat is better than deeply nested beyond two levels.