What are the five classes of HTTP status codes?

1xx (Informational: request received, continuing), 2xx (Successful: request received, understood, accepted), 3xx (Redirection: further action needed), 4xx (Client Error: request has bad syntax or cannot be fulfilled), and 5xx (Server Error: server failed to fulfill valid request).

What is the difference between 301 and 302 redirects?

301 Moved Permanently tells browsers and search engines to cache the redirection permanently and transfer SEO link equity. 302 Found (or 307 Temporary Redirect) informs clients that the resource is only temporarily at another location, preserving the original URL.

HTTP Status Codes & Headers Directory

Searchable reference manual for all RFC 9110 HTTP response status codes and standard request/response headers with definitions, cache directives, and REST API conventions. 100% private in-browser.

HTTP Protocol & REST API Standards

RFC 9110 Semantics

RFC 9110 supersedes RFC 7231 as the modern IETF specification defining core HTTP architecture, method idempotency, and status code semantics.

Modern Caching Controls

Headers like Cache-Control: no-cache, no-store, must-revalidate and conditional validators (ETag) regulate browser caching and CDN edge purging.

Zero Network Footprint

The entire catalog is indexed in-memory with real-time substring search, ensuring instant lookups even when offline or behind a firewall.