Articles & Guides

HTTP 504 Gateway Timeout — 6 causes, difference from 502, proper timeout tuning in nginx/Apache/PHP-FPM/Node.js with real config examples.

502 Bad Gateway decoded for nginx/Apache + PHP-FPM/Node.js, how it differs from 500/504, 7 causes, step-by-step fixes with config examples.

HTTP 429 explained: how rate limiting works, nginx limit_req setup, Redis sliding window, proper Retry-After handling on clients and APIs.

403 Forbidden causes and fixes: file permissions, .htaccess, nginx, WordPress, ModSecurity, IP blocks. Step-by-step diagnosis through server logs.

HTTP 503 Service Unavailable explained: how it differs from 500/502, 6 causes and fixes for nginx, Apache, PHP-FPM, Kubernetes with config examples.

301 vs 302 redirects compared: SEO impact, when to pick each, and setup examples for nginx, Apache, WordPress, PHP. Avoid common redirect mistakes.

HTTP 500 Internal Server Error decoded: 8 common causes, how to read PHP, nginx, Apache and Node.js logs, and proven fixes for WordPress, Laravel, Express.

What RFC 9110 §15.5.5 actually says about 404 Not Found: the exact wording, why a 404 is cacheable by default, how it differs from 410 and 403, plus fixes for nginx, Apache, Next.js and WordPress.

Learn how the X-Forwarded-For header works, why it matters for logging and security, trust chain configuration, and common pitfalls.

Trace every step of an HTTP request from typing a URL to seeing a rendered page. DNS, TCP, TLS, HTTP, rendering — understand the full journey.