HTTP Explained: Methods, Request Flow, and Key Status Codes
An infographic in Spanish that summarizes how an HTTP request works, the most commonly used methods, status code families and examples, a quick guide to interpreting status codes, and best practices for designing APIs.
- Complexity
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- 5 min read
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About this infographic
Editorial summary of visible content: • HTTP flow: Client → Request → Server/API → Response → Result. The request includes the method, URL, headers, and body; the response indicates what happened using a status code. • Most commonly used methods: GET (get), POST (create), PUT (replace), PATCH (partially update), DELETE (delete), HEAD (headers), OPTIONS (options). • Mnemonic: Read = GET; Create = POST; Replace = PUT; Partial Update = PATCH; Delete = DELETE. Safe methods: GET, HEAD, OPTIONS. Idempotent methods: GET, PUT, DELETE, HEAD, OPTIONS. • Status code families: 1xx Informational; 2xx Success; 3xx Redirection; 4xx Client Error; 5xx Server Error. • Key status codes shown: 100 Continue, 101 Switching Protocols; 200 OK, 201 Created, 202 Accepted, 204 No Content; 301 Moved Permanently, 302 Found, 303 See Other, 304 Not Modified, 307 Temporary Redirect, 308 Permanent Redirect; 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found, 405 Method Not Allowed, 409 Conflict, 410 Gone, 415 Unsupported Media Type, 418 I’m a teapot, 422 Unprocessable Entity, 429 Too Many Requests; 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout. • Quick interpretation: 2xx everything is fine; 3xx take another route/redirect; 4xx client problem; 5xx server problem. • Examples of requests and responses (as shown): GET /users → 200 OK; POST /users → 201 Created; POST to a private resource without a session → 401 Unauthorized; GET to a nonexistent route → 404 Not Found; PUT /users/42 → 204 No Content; DELETE /users/42 → 204 No Content. • Best practices: use semantic methods; return consistent status codes; include helpful messages; take advantage of caching and redirects when applicable; avoid using 200 OK to hide errors.
Key takeaways
- HTTP uses methods to express intent (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS).
- The basic cycle: the client sends a request; the server responds with a code that summarizes the result.
- Code families: 1xx informational, 2xx success, 3xx redirection, 4xx client error, 5xx server error.
- GET, HEAD, and OPTIONS are considered safe; GET, PUT, DELETE, HEAD, and OPTIONS are idempotent.
- Status codes: 200, 201, 204; 301–308 for redirects; 400, 401, 403, 404, 405, 409, 415, 422, 429; 500–504.
- Quick guide: 2xx means everything is okay; 3xx indicates alternative routes; 4xx is the client's fault; 5xx is the server's fault.
- Practical examples include listing, creating, updating, and deleting resources with common responses (200, 201, 204, 401, 404).
- Best practices: Use semantic methods, consistent codes, clear messages, caching/redirects, and don't hide errors with a 200 status code.
