Complete HTTP Status Codes & most commonly server error codes list

What are HTTP Status Codes?

HTTP status codes are standardized codes returned by a web server in response to a client’s request made to the server via HTTP (Hypertext Transfer Protocol). These codes are included in the HTTP header of the server’s response and provide information about the status of the request.

HTTP status codes are grouped into five categories based on their first digit:

1xx Informational: These status codes indicate that the request has been received and understood and that the process is continuing.

2xx Success: These status codes indicate that the request was successfully received, understood, and accepted.

3xx Redirection: These status codes indicate that further action needs to be taken by the client to fulfill the request. They are often used for redirection purposes.

4xx Client Error: These status codes indicate that the client’s request cannot be fulfilled due to an error on the client’s part (e.g., invalid request syntax, authentication failure).

5xx Server Error: These status codes indicate that the server encountered an error while trying to fulfill the request. It is not due to an error on the client’s part.

HTTP status codes play a crucial role in communication between clients (such as web browsers) and servers, providing information about the success or failure of a request and guiding subsequent actions. They help developers troubleshoot issues and provide feedback to users about the outcome of their requests.

Here are the names of various server error codes along with their respective HTTP status codes:

1. Continue (100)
2. Switching Protocols (101)
3. Processing (102)
4. Early Hints (103)
5. OK (200)
6. Created (201)
7. Accepted (202)
8. Non-Authoritative Information (203)
9. No Content (204)
10. Reset Content (205)
11. Partial Content (206)
12. Multi-Status (207)
13. Already Reported (208)
14. IM Used (226)
15. Multiple Choices (300)
16. Moved Permanently (301)
17. Found (302)
18. See Other (303)
19. Not Modified (304)
20. Use Proxy (305)
21. Temporary Redirect (307)
22. Permanent Redirect (308)
23. Bad Request (400)
24. Unauthorized (401)
25. Payment Required (402)
26. Forbidden (403)
27. Not Found (404)
28. Method Not Allowed (405)
29. Not Acceptable (406)
30. Proxy Authentication Required (407)
31. Request Timeout (408)
32. Conflict (409)
33. Gone (410)
34. Length Required (411)
35. Precondition Failed (412)
36. Payload Too Large (413)
37. URI Too Long (414)
38. Unsupported Media Type (415)
39. Range Not Satisfiable (416)
40. Expectation Failed (417)
41. I’m a teapot (418)
42. Misdirected Request (421)
43. Unprocessable Entity (422)
44. Locked (423)
45. Failed Dependency (424)
46. Too Early (425)
47. Upgrade Required (426)
48. Precondition Required (428)
49. Too Many Requests (429)
50. Request Header Fields Too Large (431)
51. Unavailable For Legal Reasons (451)
52. Internal Server Error (500)
53. Not Implemented (501)
54. Bad Gateway (502)
55. Service Unavailable (503)
56. Gateway Timeout (504)
57. HTTP Version Not Supported (505)
58. Variant Also Negotiates (506)
59. Insufficient Storage (507)
60. Loop Detected (508)
61. Not Extended (510)
62. Network Authentication Required (511)

Explanations of common server error codes

1. 400 Bad Request: The server cannot process the request due to a client error. This might be due to malformed syntax or invalid parameters in the request.
2. 401 Unauthorized: The request requires authentication, but the client has not provided valid credentials or the credentials are invalid.
3. 403 Forbidden: The server understood the request, but refuses to authorize it. This could be due to lack of permission to access a resource.
4. 404 Not Found: The server cannot find the requested resource. This is a common error encountered when a URL or resource does not exist.
5. 500 Internal Server Error: A generic error message indicating that something has gone wrong on the server but the server could not be more specific about the error.
6. 501 Not Implemented: The server does not support the functionality required to fulfill the request. This is often encountered when the server does not recognize the request method.
7. 502 Bad Gateway: The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to fulfill the request.
8. 503 Service Unavailable: The server is currently unable to handle the request due to temporary overloading or maintenance of the server.
9. 504 Gateway Timeout: The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server or endpoint.
10. 505 HTTP Version Not Supported: The server does not support the HTTP protocol version used in the request.
11. 507 Insufficient Storage: The server is unable to store the representation needed to complete the request. This is often due to the server running out of storage space.
12. 508 Loop Detected: The server detected an infinite loop while processing the request.
13. 509 Bandwidth Limit Exceeded: The server has exceeded the bandwidth limit allocated for the client or user.
14. 510 Not Extended: Further extensions to the request are required for the server to fulfill it.

These are some of the most commonly encountered server error codes, but there are many others as well, depending on the specific protocols and applications being used.

HTTP status codes for SEOs

HTTP status codes can have implications for search engine optimization (SEO) because they affect how search engine crawlers interact with web pages. Here are some HTTP status codes that are particularly relevant for SEO:

1. 200 OK: This status code indicates that the server successfully processed the request and returned the requested resource. It’s the ideal status code for SEO because it means the page is accessible and can be indexed by search engines.
2. 301 Moved Permanently: This status code indicates that the requested resource has been permanently moved to a new URL. 301 redirects are often used when content has been permanently moved to a new location. Properly implementing 301 redirects ensures that search engines transfer the link equity from the old URL to the new one, preserving the SEO value.
3. 302 Found (Temporary Redirect): This status code indicates that the requested resource has been temporarily moved to a new URL. However, for SEO purposes, it’s generally recommended to use 301 redirects for permanent changes rather than 302 redirects. Search engines may not pass link equity as reliably with 302 redirects.
4. 404 Not Found: This status code indicates that the requested resource could not be found on the server. While 404 errors are inevitable for websites due to content changes or removed pages, too many 404 errors can negatively impact SEO. It’s important to monitor and fix 404 errors, either by redirecting to relevant pages or by customizing a helpful 404 error page.
5. 410 Gone: Similar to a 404 error, a 410 status code indicates that the requested resource is permanently gone and will not be available again. From an SEO perspective, using a 410 status code for content that has been intentionally removed can signal to search engines that the content should be de-indexed more quickly than with a 404 error.
6. 500 Internal Server Error: This status code indicates that the server encountered an unexpected condition that prevented it from fulfilling the request. While occasional server errors are unavoidable, frequent 500 errors can negatively impact SEO by disrupting search engine crawlers’ ability to access and index content.

These are some of the key HTTP status codes that SEOs should be aware of and monitor when optimizing websites for search engines. Proper handling of these status codes can help ensure that search engines can effectively crawl, index, and rank web pages, ultimately improving the website’s visibility in search engine results.

Here is a list of common HTTP status codes, including server error codes:

1. Informational responses (1xx):
   • 100 Continue
   • 101 Switching Protocols
   • 102 Processing
   • 103 Early Hints
2. Successful responses (2xx):
   • 200 OK
   • 201 Created
   • 202 Accepted
   • 203 Non-Authoritative Information
   • 204 No Content
   • 205 Reset Content
   • 206 Partial Content
   • 207 Multi-Status
   • 208 Already Reported
   • 226 IM Used
3. Redirection messages (3xx):
   • 300 Multiple Choices
   • 301 Moved Permanently
   • 302 Found
   • 303 See Other
   • 304 Not Modified
   • 305 Use Proxy
   • 306 (Unused)
   • 307 Temporary Redirect
   • 308 Permanent Redirect
4. Client error responses (4xx):
   • 400 Bad Request
   • 401 Unauthorized
   • 402 Payment Required
   • 403 Forbidden
   • 404 Not Found
   • 405 Method Not Allowed
   • 406 Not Acceptable
   • 407 Proxy Authentication Required
   • 408 Request Timeout
   • 409 Conflict
   • 410 Gone
   • 411 Length Required
   • 412 Precondition Failed
   • 413 Payload Too Large
   • 414 URI Too Long
   • 415 Unsupported Media Type
   • 416 Range Not Satisfiable
   • 417 Expectation Failed
   • 418 I’m a teapot
   • 421 Misdirected Request
   • 422 Unprocessable Entity
   • 423 Locked
   • 424 Failed Dependency
   • 425 Too Early
   • 426 Upgrade Required
   • 428 Precondition Required
   • 429 Too Many Requests
   • 431 Request Header Fields Too Large
   • 451 Unavailable For Legal Reasons
5. Server error responses (5xx):
   • 500 Internal Server Error
   • 501 Not Implemented
   • 502 Bad Gateway
   • 503 Service Unavailable
   • 504 Gateway Timeout
   • 505 HTTP Version Not Supported
   • 506 Variant Also Negotiates
   • 507 Insufficient Storage
   • 508 Loop Detected
   • 510 Not Extended
   • 511 Network Authentication Required

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