HTTP Status Code Lookup

Search the current IANA registry, understand subtle status-code semantics, compare confusing pairs, and validate response behavior before it ships.

100% local · registry snapshot built in

Find a status

IANA snapshot

Code, phrase or scenario

Family

Semantic inspector

Choose a registered or unassigned code to inspect its semantics.

Compare two codes

First

Second

Popular confusing pairs

Use comparison when reason phrases sound similar but method preservation, authentication, retry, permanence, or cache behavior differs.

Response behavior validator

Status

Request method

Template format

Shipping checklist

Starter response

Registry-aware

Includes all currently registered 100–599 codes from the IANA registry, including temporary 104, plus unassigned-range detection.

Semantics over slogans

Highlights message-body rules, cache defaults, authentication headers, redirect method preservation and safe retry concerns.

Current terminology

Uses RFC 9110 titles such as “Content Too Large” and “Unprocessable Content” rather than older aliases.

Registry notes

IANA HTTP Status Code Registry snapshot checked September 2026. 104 is a temporary registration scheduled to expire 2026-11-13 unless extended. Codes 306 and 418 are explicitly unused; 510 is obsolete. Unassigned values are shown as such instead of inventing non-standard meanings.