REST APIs and HTTP Methods

Every HTTP interaction has the same shape. The request line includes method (POST), path, and HTTP version. Headers carry metadata (auth token, content type, content length). An optional body carries data (here, the JSON payload). The response has a status line, response headers, and a body.

#The CRUD Methods#link

Idempotency matters. An idempotent operation produces the same result whether you run it once or ten times. GET, PUT, and DELETE are idempotent. POST is not — running POST twice creates two resources. This matters for automation: if a script retries on failure, an idempotent method is safe; a non-idempotent method creates duplicates.

#Status Codes#link

• ▪200 OK — request succeeded
• ▪201 Created — new resource created (POST success)
• ▪202 Accepted — request queued for async processing (common in network controllers)
• ▪204 No Content — success, no response body (common for DELETE)
• ▪400 Bad Request — malformed request (wrong syntax, missing fields)
• ▪401 Unauthorized — missing or invalid token
• ▪403 Forbidden — valid auth, insufficient permission
• ▪404 Not Found — resource doesn't exist
• ▪409 Conflict — resource already exists (POST on existing)
• ▪429 Too Many Requests — rate limited
• ▪500 Internal Server Error — server-side failure
• ▪502/503/504 — gateway or service issues

#Request Anatomy#link

#Check Your Understanding#link