HTTP Status Codes
2xx (SUCCESS) — 200 OK (GENERIC SUCCESS), 201 Created (NAYA RESOURCE BANA), 204 No Content (SUCCESS, LEKIN RETURN karne ke liye, KUCH NAHI, jaise DELETE ke BAAD). 3xx (REDIRECTION) — 301 Moved Permanently, 304 Not Modified (CACHING ke liye).
4xx (CLIENT ERROR) — 400 Bad Request (INVALID INPUT), 401 Unauthorized (AUTHENTICATION MISSING/INVALID), 403 Forbidden (AUTHENTICATED, LEKIN PERMISSION NAHI), 404 Not Found, 409 Conflict (jaise DUPLICATE ENTRY). 5xx (SERVER ERROR) — 500 Internal Server Error (UNEXPECTED, SERVER-SIDE BUG), 503 Service Unavailable (SERVER, TEMPORARILY, OVERLOADED/DOWN).
// COMMON MAPPINGS, REST APIs mein:
// GET success → 200 OK
// POST success (create) → 201 Created
// DELETE success → 204 No Content
// Invalid request body → 400 Bad Request
// Missing/invalid token → 401 Unauthorized
// Valid token, NO permission → 403 Forbidden
// Resource NOT found → 404 Not Found
// Duplicate/conflict → 409 Conflict
// Unexpected server bug → 500 Internal Server Error- 2xx = success, 3xx = redirection, 4xx = client error, 5xx = server error
- 401 = "tum kaun ho, pata nahi" — 403 = "pata hai, lekin permission nahi"
- Proper status codes = client, response body parse kiye BINA, result samajh leta hai
400 Bad Request, TYPICALLY, MALFORMED SYNTAX (jaise, INVALID JSON) ke liye hai. 422 Unprocessable Entity, TAB USE hota hai, JAB, SYNTAX, CORRECT hai (VALID JSON), LEKIN, SEMANTIC VALIDATION, FAIL hoती hai (jaise, EK REQUIRED FIELD, MISSING hai) — YE, DISTINCTION, SUBTLE hai, aur, MANY APIs, 400 hi, DONO SCENARIOS ke liye, USE karte hain.
- 400 = malformed request (INVALID JSON syntax)
- 422 = SYNTACTICALLY valid, LEKIN, semantic validation FAIL
502 Bad Gateway (UPSTREAM SERVER SE, INVALID RESPONSE), 503 Service Unavailable (SERVER, TEMPORARILY, OVERLOADED, MAINTENANCE mein), 504 Gateway Timeout (UPSTREAM SERVER, TIMEOUT ho gaya) — YE, MICROSERVICES/PROXY, ARCHITECTURES mein, COMMON, ERROR CODES hain.