HTTP 402 Payment Required vs 501 Not Implemented
HTTP 402 (Payment Required) is a 4xx Client Error response, while 501 (Not Implemented) is a 5xx Server Error response. 402 indicates that reserved for future use. Originally intended for digital payment systems, some APIs use it to indicate a billing or subscription issue. In contrast, 501 means that the server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
Description
Reserved for future use. Originally intended for digital payment systems, some APIs use it to indicate a billing or subscription issue.
When You See It
On some APIs when a subscription has expired or payment is needed.
How to Fix
Check your billing status, update payment method, or upgrade your subscription.
Description
The server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
When You See It
When using an HTTP method (like PATCH) that the server doesn't support.
How to Fix
Use a different HTTP method that the server supports. Check server documentation.
Key Differences
402 is a 4xx Client Error response, while 501 is a 5xx Server Error response.
HTTP 402: Reserved for future use. Originally intended for digital payment systems, some APIs use it to indicate a billing or subscription issue.
HTTP 501: The server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
You encounter 402 when on some APIs when a subscription has expired or payment is needed.
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
When to Use Which
For 402 (Payment Required): Check your billing status, update payment method, or upgrade your subscription. For 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation.