About HTTP Status Codes – Lookup & Debug Server Responses Fast
Returning 200 for everything — including errors — is one of the most common API design mistakes. It breaks monitoring tools, confuses API consumers, and violates HTTP semantics that caches and load balancers depend on. This reference documents every standard HTTP status code from 100 through 511 with plain English explanations of when servers return each code, what action the client should take, and practical troubleshooting tips for the most frequently encountered errors. Search by code number or keyword to find any status code instantly.
How to Use This Tool
Follow these simple steps to get accurate results in seconds. The whole process takes less than a minute for most inputs.
- 1
Browse or Search for a Code
Scroll through categorized sections (1xx–5xx) or type a code number or keyword into the search field to find it instantly.
- 2
Read the Code Description
Each entry shows the code, official name, explanation of when servers return it, and common causes. Pay attention to similar codes like 301 vs 302 or 401 vs 403.
- 3
Review Troubleshooting Guidance
For error codes, check the practical tips on common causes and recommended fixes to move from understanding to resolution.
- 4
Copy for Documentation
Click any status code to copy its code number and description for API documentation, code comments, or incident reports.
How It Works
The technical details of how this tool processes your input and produces accurate results.
Categorized Code Organization
Status codes are organized by their first digit: 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors. Within each category, codes are listed numerically with quick-jump navigation. This first-digit grouping means even an unfamiliar code (like 418 or 425) can be immediately understood by its category.
Keyword and Code Search
The search algorithm matches against the numeric code, official name, and plain-language description. Typing '401' returns that specific code; typing 'unauthorized' returns both 401 and 403 with their distinctions highlighted; typing 'redirect' surfaces all 3xx codes with their SEO implications.
Copy-Ready Documentation Output
Each status code entry includes the code number, official name, plain-language explanation, common causes, and recommended client action. Click any entry to copy the code and description for API documentation, code comments, or incident reports.
Key Features
Built to handle real workflows quickly and accurately. Each feature solves a specific problem you'd otherwise need multiple tools or manual steps to address.
Complete RFC Status Code Coverage
Every standard HTTP status code from 100 through 511 is documented with its official name, plain-language description, and common scenarios — including less familiar codes like 418 and 429.
Category-Based Navigation
Codes grouped into 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors with quick-jump navigation to each category.
Instant Search by Code or Keyword
Type a status code (404) or keyword (timeout) to filter the list instantly. Faster than scrolling when you know the code but need to confirm its exact meaning.
Troubleshooting Guidance for Error Codes
Each error code includes practical tips on common causes and recommended fixes — helping you move from understanding the code to resolving the issue.
One-Click Copy for Documentation
Click any status code to copy its code and description for API documentation, error handling comments, or incident reports.
Benefits of Using HTTP Status Codes – Lookup & Debug Server Responses Fast
Why this tool matters and how it improves your daily work.
Resolve the 401 vs. 403 Confusion
401 means 'authenticate and retry' — the client lacks valid credentials. 403 means 'authenticated but not allowed' — the credentials are valid but insufficient. Mixing these up breaks authentication flows and confuses API consumers. This reference makes the distinction unambiguous with concrete examples.
SEO-Correct Redirect Choices
A 301 redirect permanently transfers SEO link equity to the new URL; a 302 keeps it with the original. Choosing the wrong redirect type can significantly impact search rankings. This reference explains the SEO implications of every 3xx code so you make the correct choice the first time.
Semantically Correct API Responses
Returning 200 OK for a successful resource creation is technically valid, but 201 Created is semantically correct — it tells API consumers and intermediary caches that a new resource was created. This reference helps you choose the most specific status code for each API response.
Faster Incident Response for 5xx Errors
When monitoring dashboards spike with 502 errors, you need to know immediately: is the upstream server down, or is the gateway misconfigured? The troubleshooting guidance for each 5xx code tells you where to look first, reducing mean time to resolution.
Common Use Cases
Real scenarios where this tool saves time and produces better results than manual methods.
REST API Endpoint Design
Look up the most appropriate status code for each API response during endpoint design. Use 201 for resource creation, 204 for successful deletion, and 422 for validation errors — not a generic 200 for everything.
Incident Response for 5xx Spikes
Reference status codes during incident response when monitoring shows spikes in 5xx errors. Quickly confirm what each code means to assess severity and identify the failure point — gateway (502), service unavailable (503), or timeout (504).
API Documentation Accuracy
Verify the correct status code names and descriptions when documenting API error responses. Avoid the common error of confusing 401 Unauthorized (needs authentication) with 403 Forbidden (authenticated but not permitted).
Technical Interview Preparation
Study the full range of HTTP status codes organized by category to prepare for backend engineering interviews that test knowledge of HTTP semantics beyond the familiar 200, 404, and 500.
Who Uses This Tool
API Developers
looking up the most semantically correct status code for each API response during endpoint design, ensuring their REST API returns 201 for resource creation and 422 for validation errors instead of a generic 200 for everything
Site Reliability Engineers
referencing status codes during incident response when monitoring dashboards show spikes in 5xx errors, quickly confirming what each specific code means to assess severity and identify the failure point
Technical Writers
verifying the correct status code names and descriptions when documenting API error responses, avoiding the common error of confusing 401 Unauthorized (needs authentication) with 403 Forbidden (authenticated but not permitted)
Pro Tips
Practical advice to get the most out of this tool, based on how experienced users actually work with it.
When designing REST APIs, always return the most specific status code available. Returning 200 for everything and encoding errors in the response body defeats the purpose of HTTP semantics and makes it harder for caches, load balancers, and monitoring tools to work correctly.
Keep 429 Too Many Requests in mind when building public-facing APIs. Implementing rate limiting with proper 429 responses from the start prevents abuse and is much harder to retrofit after launch. Include a Retry-After header so clients know when to retry.
During debugging, pay close attention to 3xx redirect chains. Multiple sequential redirects significantly slow page load times, and redirect loops from misconfigured HTTPS rules are a common source of mysterious browser errors.
Frequently Asked Questions
Quick answers to the most common questions about this tool. If your question isn't here, contact our support team.