HTTP Status Code Checker
Search and browse all HTTP status codes with descriptions, causes, and fixes.
What is an HTTP Status Checker?
An HTTP status checker is a reference tool that helps developers, SEO professionals, and system administrators quickly look up and understand HTTP status codes. Every time your browser requests a web page, the server responds with a three-digit status code that indicates what happened — whether the request succeeded, was redirected, or encountered an error.
This comprehensive HTTP status checker covers all standard status codes organized by category: 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client errors), and 5xx (server errors). For each code, you'll find a clear description, common causes, and practical guidance on how to fix issues. Whether you need to check HTTP headers during debugging, understand why a page returns a specific status, or quickly reference the difference between a 301 and 302 redirect, this tool has you covered — instantly, with no signup required.
How to Use the HTTP Status Checker
- Search by code or keyword. Type a status code number (e.g., "404") or a keyword (e.g., "not found", "redirect") into the search box. Results filter instantly as you type.
- Filter by category. Use the category buttons to filter by status code range: 1xx for informational, 2xx for success, 3xx for redirections, 4xx for client errors, and 5xx for server errors.
- Click to expand details. Click any status code to reveal its full description, including what causes it, what it means for your users, and how to resolve it if it's an error.
- Use popular codes for quick access. The most commonly encountered codes (200, 301, 404, 500, etc.) are highlighted for fast lookup — perfect when you're in the middle of debugging.
- Bookmark for reference. Keep this page bookmarked as your go-to HTTP status code reference. It loads instantly and works offline once cached.
Features
- Complete status code reference: Covers all standard HTTP status codes from 100 to 599, including commonly used codes and lesser-known ones like 418 (I'm a Teapot) and 451 (Unavailable for Legal Reasons).
- Color-coded categories: Each category (1xx–5xx) has its own color, making it easy to visually distinguish between informational responses, successes, redirects, and errors at a glance.
- Instant search: Search by code number or keyword with real-time filtering. No page reloads or waiting — results appear as you type.
- Causes and fixes: Each status code includes practical information about common causes and actionable steps to resolve issues, going beyond just the definition.
- Popular codes highlighted: The most frequently encountered status codes are prominently displayed for quick reference during debugging sessions.
- Fully offline-capable: Once loaded, the entire reference works without an internet connection. Perfect for debugging server issues when connectivity is intermittent.
- Mobile-friendly: Responsive design works on phones, tablets, and desktops. Look up status codes from your phone while SSH'd into a server from your laptop.
Use Cases
- Debugging API responses: When your API returns an unexpected status code, quickly look up what it means and why it might be happening. Understand the difference between 400 (bad request), 401 (unauthorized), and 403 (forbidden) to pinpoint the issue.
- SEO auditing: Search engines treat different status codes very differently. Use this reference to understand how 301 vs 302 redirects affect your SEO, what a 410 (Gone) signals to crawlers, and why soft 404s hurt your rankings.
- Server configuration: When setting up redirects, error pages, or access controls on Apache, Nginx, or other servers, reference the correct status codes to ensure proper behavior and HTTP compliance.
- Learning web development: Students and junior developers can use this as a study reference to understand HTTP fundamentals. The clear descriptions and real-world causes make abstract concepts concrete.
- Monitoring and alerting: When your monitoring system reports unusual status codes, quickly determine severity. Is a 502 (Bad Gateway) a critical outage or a transient load balancer issue?
- QA and testing: During testing, verify that your application returns the correct status codes for different scenarios — 201 for resource creation, 204 for successful deletion, 422 for validation errors, etc.
Tips & Tricks
- Use browser dev tools alongside: Open your browser's Network tab (F12 → Network) to see actual HTTP status codes for every request, then use this checker to understand any unexpected codes you see.
- Know the key redirects: 301 (permanent) passes full SEO value to the new URL. 302 (temporary) tells search engines to keep indexing the original URL. 307 and 308 are their HTTP/1.1 equivalents that preserve the request method.
- Distinguish 4xx errors: 400 = malformed request, 401 = needs authentication, 403 = authenticated but not authorized, 404 = not found, 405 = wrong HTTP method, 429 = rate limited. Each requires a different fix.
- Check HTTP headers for context: Status codes tell you what happened, but response headers tell you why. Look for headers like Retry-After (with 429/503), Location (with 3xx), and WWW-Authenticate (with 401) for additional debugging clues.
- Use 410 for removed content: If you permanently remove a page, return 410 (Gone) instead of 404. This tells search engines to remove the URL from their index faster than a 404 would.
HTTP Status Checker vs Alternatives
There are several HTTP status code references available online, including MDN Web Docs, Wikipedia, and various developer tools. While MDN is excellent for deep technical documentation, it requires navigating between individual pages for each status code and doesn't offer search or filtering.
Other HTTP status checker tools often focus on actively checking URLs (sending requests to see what status code a live URL returns), which is a different use case. Some require you to enter a URL and wait for a server response, which isn't helpful when you just need to quickly look up what a code means.
ToolMagic's HTTP status checker is a fast, searchable, offline-capable reference that puts all status codes in one place with instant search, category filtering, and practical fix guidance. It's completely free, requires no signup, and works entirely in your browser. Think of it as your personal HTTP cheat sheet that's always a bookmark away.
Frequently Asked Questions
What does a 404 error mean?
A 404 (Not Found) status code means the server couldn't find the requested resource at the given URL. Common causes include deleted pages, changed URLs without proper redirects, typos in links, or broken bookmarks. To fix it, set up a 301 redirect to the new URL, restore the missing content, or create a helpful 404 error page that guides users to relevant content.
What is the difference between 301 and 302 redirects?
A 301 is a permanent redirect — it tells browsers and search engines that the resource has moved permanently to a new URL. Search engines transfer SEO value (link juice) to the new URL. A 302 is a temporary redirect — it indicates the move is temporary, so search engines continue to index the original URL. Use 301 for permanent URL changes and 302 for temporary situations like maintenance or A/B testing.
What causes a 500 Internal Server Error?
A 500 error is a generic server-side error indicating something went wrong but the server can't be more specific. Common causes include bugs in server-side code, misconfigured server settings, database connection failures, exhausted server resources, or unhandled exceptions. Check your server error logs for the specific cause — the 500 code itself is just a catch-all.
What does a 200 status code mean?
200 (OK) is the standard success response. It means the server successfully processed the request and returned the requested content. For GET requests, the response body contains the resource. For POST requests, it typically contains the result of the action. A 200 status is what you want to see for every normal page load.
What is a 403 Forbidden error?
A 403 (Forbidden) means the server understood the request but refuses to authorize it. Unlike 401 (Unauthorized), authentication won't help — the server knows who you are but you don't have permission. Common causes include incorrect file permissions, IP-based access restrictions, disabled directory listing, or access control rules blocking the request.
What is the difference between 401 and 403?
401 (Unauthorized) means "you haven't proven who you are" — the request lacks valid authentication credentials. Providing correct credentials (login) should fix it. 403 (Forbidden) means "I know who you are, but you're not allowed" — you're authenticated but lack the necessary permissions. The fix for 403 is adjusting permissions, not re-authenticating.
What does a 502 Bad Gateway mean?
A 502 error means a server acting as a gateway or proxy received an invalid response from an upstream server. This commonly happens with reverse proxies (like Nginx) when the backend application server (like Node.js, PHP-FPM, or Gunicorn) is down, overloaded, or returning malformed responses. It's usually a server-side issue that requires checking backend service health.
Does this tool check live URLs?
This tool is a reference guide — it helps you look up and understand HTTP status codes. It doesn't send HTTP requests to live URLs. If you need to check what status code a specific URL returns, use your browser's dev tools (Network tab) or command-line tools like curl.
Related Tools
Explore more free developer tools on ToolMagic:
- CSS Optimizer — Minify and compress CSS for faster page loads and better performance scores.
- JSON to CSV Converter — Convert API response data from JSON to CSV for analysis and reporting.