Articles & Guides

HTTP

HTTP 502 Bad Gateway: What It Means and How to Fix

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.

15.04.2026 · 5 min · 616 views

HTTP

429 Too Many Requests: How Long to Wait and How to Fix It

429 Too Many Requests means you hit a rate limit. Wait for Retry-After or back off exponentially; developers can tune nginx limit_req and send Retry-After.

15.04.2026 · 15 min · 820 views

HTTP

403 Forbidden Error: Fixes for Visitors, nginx, Apache and APIs

403 Forbidden error: find who refused you (Cloudflare, nginx, Apache, WAF, app) from headers and logs, then fix it on Chrome, iPhone, Postman or your server.

15.04.2026 · 15 min · 869 views

HTTP

503 Service Unavailable: Meaning (RFC 9110) and Fixes

503 Service Unavailable (RFC 9110, 15.6.4): the server is overloaded or in maintenance, usually briefly. Retry-After plus nginx, PHP-FPM, IIS fixes.

15.04.2026 · 12 min · 828 views

HTTP

HTTP 301 vs 302 Redirect: Differences and When to Use Each

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

15.04.2026 · 4 min · 690 views

HTTP

500 Internal Server Error: How to Fix It on nginx, Apache, IIS

500 Internal Server Error explained: whose fault it is, whether it fixes itself, real log strings and fixes for nginx, Apache, IIS, WordPress and Cloudflare.

15.04.2026 · 15 min · 1200 views

HTTP

How to Fix 404 Not Found Errors: Visitors, nginx, Apache, CDN

Fix a 404 Not Found error: quick checks for visitors, then find which layer answers 404 (CDN, nginx, Apache or the app) with curl and logs, and fix it.

15.04.2026 · 19 min · 2585 views

HTTP

X-Forwarded-For Header: Understanding Client IP Behind Proxies

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

16.03.2026 · 4 min · 619 views

HTTP

HTTP Request Lifecycle: DNS, TCP, TLS, Request, Response

The HTTP request lifecycle step by step: URL parsing, DNS lookup, TCP connect, TLS handshake, request, server processing and response, and what fails.

16.03.2026 · 4 min · 1227 views

HTTP

Server-Sent Events vs WebSockets: Which to Use for Realtime

Compare SSE and WebSockets for real-time web communication. Learn when to use each, their performance characteristics, and implementation patterns.

16.03.2026 · 5 min · 1294 views