About
☰
All Tools
Categories
Blog About

HTTP Status Code Reference – Lookup 100–599 Responses

Search any HTTP status code to get category, description, RFC reference, and real-world usage for APIs and websites.

🟢 Runs locally · no uploads

HTTP Status Codes

Reference guide for HTTP status codes

200
OK
201
Created
204
No Content
301
Moved Permanently
302
Found
304
Not Modified
400
Bad Request
401
Unauthorized
403
Forbidden
404
Not Found
409
Conflict
500
Internal Server Error
502
Bad Gateway
503
Service Unavailable

Related tools

Show more

URL Parser & Analyzer

Parse and analyze URLs to extract all components including protocol, hostname, path, query parameters, fragments, with security analysis and validation features.

IP Subnet Calculator - Netmask & CIDR Calculator

Calculate IP subnets, netmasks, CIDR notation, and find first/last usable IP addresses. Complete network calculator with subnet splitting and binary analysis for network engineers.

JSON Formatter & Validator

Stop squinting at minified JSON! Format and validate JSON instantly with automatic error detection, syntax highlighting, and pretty printing. Catches missing quotes, trailing commas, and invalid syntax. Works with JSON and JSONC. Perfect for debugging API responses and config files. Free, works offline, unlimited usage.

HTTP Header Analyzer

Inspect HTTP response headers, spot missing security controls, and get performance & caching recommendations in seconds.

CSS Minifier

Stop using bloated CSS files! Minify and compress CSS instantly by removing whitespace, comments, and optimizing properties for 30-40% smaller file sizes. Improves page load speed, reduces bandwidth, and optimizes for production. Supports modern CSS including variables, Grid, Flexbox, and media queries. Free, works offline, unlimited minification.
Show more

HTML Minifier

Stop deploying bloated HTML files! Compress and optimize HTML code instantly by removing unnecessary whitespace, comments, empty elements, and redundant attributes for production deployment. Reduces file size by 20-40% for faster page loads. Free, works offline, unlimited minification.

JavaScript Minifier

Stop deploying uncompressed JavaScript! Minify and compress JavaScript code instantly by removing comments, whitespace, and optimizing syntax for production use. Reduces file size by 30-60% for faster page loads. Supports ES6+, async/await, and modern JavaScript. Free, works offline, unlimited minification.

CSS Selector Generator

Stop manually writing complex CSS selectors! Generate precise selectors for targeting HTML elements instantly with support for classes, IDs, attributes, pseudo-classes, and complex combinators. Includes specificity calculation and XPath conversion. Perfect for web scraping and styling. Free, works offline, unlimited generation.

CSS Grid Generator

Generate CSS Grid layouts with visual editor, responsive breakpoints, named areas, and custom positioning. Create complex grid systems with HTML and CSS code generation.

SVG Optimizer

Optimize and compress SVG files by removing unnecessary elements, attributes, and metadata. Advanced cleaning options to reduce file size while preserving visual quality.
› About this tool · FAQ

Stop searching for HTTP status code meanings! Complete reference guide with detailed descriptions, usage examples, RFC references, and practical guidance for web developers and API designers. Covers all codes from 100 to 599 with real-world examples. Free, works offline, searchable.

What are the main HTTP status code categories?

1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error). Each category indicates the type of response from the server.

When should I use 422 vs 400?

Use 400 for malformed requests (syntax errors), and 422 for well-formed requests that fail semantic validation (business logic errors).

What's the difference between 401 and 403?

401 means authentication is required or failed (login needed), while 403 means the user is authenticated but lacks permission for the resource.

Which status codes are most commonly used?

Most common: 200 (OK), 201 (Created), 204 (No Content), 301/302 (Redirects), 400 (Bad Request), 401 (Unauthorized), 403 (Forbidden), 404 (Not Found), 422 (Unprocessable Entity), 500 (Internal Server Error), 502 (Bad Gateway), 503 (Service Unavailable).

How do I choose between 301 and 302 redirects?

Use 301 for permanent redirects (SEO juice transfers, caching encouraged) and 302 for temporary redirects (original URL will be used again).