Look Up Any HTTP Status Code Instantly (200, 404, 500 Explained)

How to Use HTTP Status Code Checker

HTTP Status Code Checker is a quick reference tool for understanding HTTP status codes returned by web servers and APIs. Whether you're debugging web applications, building APIs, or troubleshooting errors, this tool provides instant explanations and solutions.

Quick Start Guide

1. Enter Status Code: Type any HTTP status code in the search box (e.g., 200, 404, 500)
2. View Details: Instantly see the meaning, category, and description
3. Understand Causes: Learn common reasons why this code appears
4. Get Solutions: Review how to fix issues related to the status code
5. Copy Code: Click "Copy Code" to copy for reference

Understanding HTTP Status Codes

What are HTTP Status Codes?

HTTP status codes are three-digit numbers returned by web servers in response to HTTP requests. They indicate whether the request succeeded, failed, or requires additional action.

Format: XXX Status Message

Examples:

• 200 OK - Success
• 404 Not Found - Resource not found
• 500 Internal Server Error - Server error

Status Code Categories:

• 1xx (Informational): Request received, continuing process
• 2xx (Success): Request successfully received and processed
• 3xx (Redirection): Further action needed to complete request
• 4xx (Client Error): Request contains errors or cannot be fulfilled
• 5xx (Server Error): Server failed to fulfill valid request

Common Use Cases

1. Debugging 404 Errors

Status Code: 404 Not Found

What it means: The requested resource could not be found on the server.

Common causes:

• Wrong URL or typo in path
• Resource has been deleted
• Incorrect API endpoint

How to fix:

• Check URL spelling
• Verify the resource exists
• Review API documentation for correct endpoint

2. Understanding 500 Errors

Status Code: 500 Internal Server Error

What it means: The server encountered an unexpected error.

Common causes:

• Server bugs or crashes
• Unhandled exceptions
• Configuration errors

How to fix:

• Check server logs for details
• Debug application code
• Contact server administrator

3. Handling Authentication (401)

Status Code: 401 Unauthorized

What it means: Authentication is required and has failed.

Common causes:

• Missing authentication token
• Invalid credentials
• Expired session

How to fix:

• Provide valid authentication
• Check username/password
• Refresh auth token or login again

4. Rate Limiting (429)

Status Code: 429 Too Many Requests

What it means: Too many requests sent in a given time period.

Common causes:

• Exceeded API rate limits
• Too many requests in short time
• DDoS protection triggered

How to fix:

• Wait before retrying (check Retry-After header)
• Implement request throttling
• Reduce request frequency

5. Successful Requests (200)

Status Code: 200 OK

What it means: The request was successful.

Common causes:

• Successful GET request
• Data retrieved successfully
• Operation completed

How to fix:

• No fix needed - this is success!

6. Redirects (301)

Status Code: 301 Moved Permanently

What it means: Resource permanently moved to new URL.

Common causes:

• URL restructuring
• Domain changes
• SEO redirects

How to fix:

• Update bookmarks to new URL
• Follow the Location header
• Update all references permanently

Status Code Categories Explained

1xx - Informational

These codes indicate that the request was received and is being processed.

• 100 Continue: Client should continue with request
• 101 Switching Protocols: Server is switching protocols (e.g., WebSocket)

2xx - Success

These codes indicate the request was successfully received, understood, and accepted.

• 200 OK: Standard success response
• 201 Created: Resource successfully created
• 202 Accepted: Request accepted for processing
• 204 No Content: Success but no content to return
• 206 Partial Content: Partial content delivered (video streaming)

3xx - Redirection

These codes indicate the client must take additional action to complete the request.

• 301 Moved Permanently: Resource permanently moved
• 302 Found: Resource temporarily at different URL
• 304 Not Modified: Cached version is still valid
• 307 Temporary Redirect: Temporary redirect, method unchanged
• 308 Permanent Redirect: Permanent redirect, method unchanged

4xx - Client Errors

These codes indicate the request contains errors or cannot be processed.

• 400 Bad Request: Malformed request syntax
• 401 Unauthorized: Authentication required
• 403 Forbidden: Server refuses to authorize
• 404 Not Found: Resource not found
• 405 Method Not Allowed: HTTP method not supported
• 408 Request Timeout: Server timed out
• 409 Conflict: Request conflicts with server state
• 410 Gone: Resource permanently deleted
• 413 Payload Too Large: Request body too large
• 415 Unsupported Media Type: Media type not supported
• 422 Unprocessable Entity: Validation errors
• 429 Too Many Requests: Rate limit exceeded

5xx - Server Errors

These codes indicate the server failed to fulfill a valid request.

• 500 Internal Server Error: Generic server error
• 501 Not Implemented: Functionality not supported
• 502 Bad Gateway: Invalid response from upstream server
• 503 Service Unavailable: Server temporarily unavailable
• 504 Gateway Timeout: Upstream server timeout

Technical Details

Status Code Structure:

XXX Status-Message

• First digit: Category (1-5)
• Full code: Specific status (100-599)
• Message: Human-readable description

How Browsers Handle Status Codes:

• 2xx: Display content normally
• 3xx: Follow redirects automatically
• 4xx: Show error page or handle in JavaScript
• 5xx: Show server error page

Response Headers:

Common headers accompanying status codes:

• Location: New URL for redirects (3xx)
• Retry-After: When to retry (429, 503)
• WWW-Authenticate: Authentication method (401)
• Content-Type: Response content type

Best Practices

For Developers:

API Development:

// Return appropriate status codes res.status(200).json({ data: result }) // Success res.status(201).json({ id: newId }) // Created res.status(400).json({ error: "Invalid" }) // Bad request res.status(404).json({ error: "Not found" }) // Not found res.status(500).json({ error: "Server error" }) // Server error

Error Handling:

fetch('/api/data') .then(response => { if (response.status === 404) { console.log('Resource not found') } else if (response.status === 500) { console.log('Server error') } return response.json() })

Proper Status Code Selection:

• Use 200 for successful GET requests
• Use 201 for successful resource creation
• Use 204 for successful DELETE with no response
• Use 400 for validation errors
• Use 401 for authentication failures
• Use 403 for authorization failures
• Use 404 for missing resources
• Use 422 for semantic errors
• Use 500 for unexpected server errors
• Use 503 for maintenance mode

Troubleshooting Guide

Problem: Getting 404 errors

Quick fixes:

1. Check URL for typos
2. Verify the endpoint exists
3. Check API version in URL
4. Review routing configuration

Problem: Getting 500 errors

Quick fixes:

1. Check server logs
2. Look for unhandled exceptions
3. Verify database connectivity
4. Check configuration files

Problem: Getting 401 errors

Quick fixes:

1. Check if auth token is included
2. Verify token hasn't expired
3. Confirm correct authentication method
4. Re-login if session expired

Problem: Getting 403 errors

Quick fixes:

1. Check user permissions
2. Verify resource ownership
3. Review access control rules
4. Contact administrator for access

Problem: Getting 429 errors

Quick fixes:

1. Wait before retrying
2. Implement exponential backoff
3. Reduce request frequency
4. Cache responses when possible

Common Debugging Scenarios

Scenario 1: API Integration

You're integrating with a third-party API and getting unexpected status codes.

Solution:

• Check API documentation for expected status codes
• Use this tool to understand what each code means
• Implement proper error handling for each code
• Log status codes for debugging

Scenario 2: Web Application Errors

Users report seeing error pages on your website.

Solution:

• Check browser console for status codes
• Use this tool to understand the errors
• Review server logs for 5xx errors
• Fix routing for 404 errors

Scenario 3: File Uploads Failing

File uploads return 413 or 400 errors.

Solution:

• 413: Increase server upload limit
• 400: Check file validation logic
• Verify Content-Type headers
• Review file size restrictions

Scenario 4: Authentication Issues

Users can't log in or access protected routes.

Solution:

• 401: Check authentication credentials
• 403: Verify user has required permissions
• Check token expiration
• Review authentication middleware

Browser Compatibility

This tool works in all modern browsers:

• ✅ Chrome/Edge (latest)
• ✅ Firefox (latest)
• ✅ Safari (latest)
• ✅ Opera (latest)

Required Features:

• JavaScript enabled
• Clipboard API (for copy functionality)

Privacy & Security

Client-Side Processing:

All status code lookups happen entirely in your browser. Your searches:

• Never leave your device
• Are not sent to any server
• Are not logged or stored
• Disappear when you close/refresh the page

Safe for Sensitive Projects:

You can safely look up status codes while:

• Debugging production issues
• Developing proprietary APIs
• Troubleshooting client projects

Advanced Use Cases

Custom Status Codes:

Some applications use custom codes in the standard ranges:

420 - Custom error (Twitter: Enhance Your Calm) 449 - Microsoft: Retry With 509 - Bandwidth Limit Exceeded

RESTful API Design:

Proper status code usage for REST APIs:

GET requests:

• 200: Resource found
• 404: Resource not found

POST requests:

• 201: Resource created
• 400: Invalid data
• 409: Duplicate resource

PUT requests:

• 200: Resource updated
• 201: Resource created
• 404: Resource not found

DELETE requests:

• 204: Resource deleted
• 404: Resource not found

Webhooks:

Handle webhook responses:

200/201: Webhook processed 4xx: Webhook will retry 5xx: Webhook will retry

Load Balancer Health Checks:

Common status codes:

200: Healthy 503: Unhealthy (remove from pool)

Status Code Reference Tables

Most Common Codes:

Code	Message	Use Case
200	OK	Successful request
201	Created	Resource created
204	No Content	Successful delete
301	Moved Permanently	Permanent redirect
400	Bad Request	Invalid request
401	Unauthorized	Authentication failed
403	Forbidden	No permission
404	Not Found	Resource missing
500	Internal Server Error	Server error
503	Service Unavailable	Server down

API Development Priority:

Must implement:

• 200, 201, 204 (success)
• 400, 404 (client errors)
• 500 (server error)

Should implement:

• 401, 403 (auth errors)
• 422 (validation)
• 429 (rate limiting)

Optional:

• 301, 302 (redirects)
• 503 (maintenance)

Tips & Tricks

1. Use Examples: Click example buttons to see common status codes
2. Learn Categories: Understand 2xx, 3xx, 4xx, 5xx meanings
3. Check Headers: Use browser DevTools to see status codes
4. Implement Properly: Return correct codes in your APIs
5. Handle All Codes: Prepare for unexpected status codes
6. Log Status Codes: Track errors in production
7. Test Edge Cases: Verify status codes in testing
8. Document APIs: List possible status codes in API docs