# HTTP Status Codes Quick reference for all HTTP response status codes. ## 1xx Informational ### 100 #### Continue The server has received the request headers and the client should proceed to send the request body. ### 101 #### Switching Protocols The requester has asked the server to switch protocols and the server has agreed. ### 102 #### Processing The server has received and is processing the request, but no response is available yet. ## 2xx Success ### 200 #### OK The request was successful. Standard response for successful HTTP requests. ### 201 #### Created The request has been fulfilled and a new resource has been created. ### 202 #### Accepted The request has been accepted for processing, but processing is not complete. ### 204 #### No Content The server successfully processed the request but is not returning any content. ### 206 #### Partial Content The server is delivering only part of the resource due to a range header sent by the client. ## 3xx Redirection ### 301 #### Moved Permanently The resource has been permanently moved to a new URL. Future requests should use the new URL. ### 302 #### Found The resource resides temporarily under a different URL. Client should continue using the original URL. ### 304 #### Not Modified The resource has not been modified since the last request. Used for caching. ### 307 #### Temporary Redirect The request should be repeated with another URL, but future requests should use the original URL. ### 308 #### Permanent Redirect The request and all future requests should be repeated using another URL. Method and body are preserved. ## 4xx Client Error ### 400 #### Bad Request The server cannot process the request due to a client error (malformed syntax, invalid framing, etc.). ### 401 #### Unauthorized Authentication is required and has failed or has not been provided. ### 403 #### Forbidden The client does not have permission to access the requested resource. ### 404 #### Not Found The requested resource could not be found on the server. ### 405 #### Method Not Allowed The request method is not supported for the requested resource. ### 408 #### Request Timeout The server timed out waiting for the request from the client. ### 409 #### Conflict The request could not be completed due to a conflict with the current state of the resource. ### 410 #### Gone The resource is no longer available and will not be available again. ### 413 #### Payload Too Large The request entity is larger than the server is willing or able to process. ### 415 #### Unsupported Media Type The request entity has a media type which the server does not support. ### 422 #### Unprocessable Entity The request was well-formed but semantically erroneous. Common in API validation errors. ### 429 #### Too Many Requests The user has sent too many requests in a given amount of time (rate limiting). ## 5xx Server Error ### 500 #### Internal Server Error A generic error message when the server encounters an unexpected condition. ### 501 #### Not Implemented The server does not recognize the request method or lacks the ability to fulfill the request. ### 502 #### Bad Gateway The server received an invalid response from the upstream server while acting as a gateway. ### 503 #### Service Unavailable The server is currently unable to handle the request due to overloading or maintenance. ### 504 #### Gateway Timeout The server did not receive a timely response from the upstream server. ## Understanding HTTP Status Codes HTTP status codes are three-digit numbers returned by a server in response to a client request. They are grouped into five categories: 1xx (Informational) indicates the request was received and processing continues; 2xx (Success) confirms the request was successfully received, understood, and accepted; 3xx (Redirection) tells the client further action is needed to complete the request; 4xx (Client Error) signals that the request contains bad syntax or cannot be fulfilled; and 5xx (Server Error) means the server failed to fulfill a valid request. In the context of REST APIs and webhook delivery, status codes are essential for communication between services. When a webhook provider sends a payload to your endpoint, the status code your server returns determines whether the delivery is considered successful or needs to be retried. Most webhook providers treat any 2xx response as a successful delivery and will retry on 4xx or 5xx errors using exponential backoff strategies. ## Most Common Status Codes for Webhooks ### 200 OK The webhook was received and processed successfully. This is the most common success response and tells the provider to mark the delivery as complete. ### 201 Created The webhook triggered the creation of a new resource on your end. Functionally equivalent to 200 for most webhook providers. ### 401 Unauthorized The webhook request failed authentication. This typically means the signature verification failed or the API key/token is missing or invalid. Check your webhook secret configuration. ### 404 Not Found The webhook endpoint URL does not exist. Double-check the URL configured in the provider's settings. This often happens after endpoint paths change during deployments. ### 429 Too Many Requests Your server is rate-limiting incoming webhooks. The provider should back off and retry later. If you see this frequently, consider increasing your rate limits or adding a queue. ### 500 Internal Server Error Your webhook handler crashed or threw an unhandled exception. Providers will typically retry the delivery. Check your server logs to identify and fix the root cause. ### 502 Bad Gateway A reverse proxy or load balancer in front of your server received an invalid response. Common when your application server is down or restarting during a deployment. ## FAQ ### What status code should my webhook endpoint return? Return `200` or `202` to acknowledge receipt of the webhook. A 200 means you processed it immediately; a 202 means you accepted it for later processing. Most providers will retry the delivery if they receive a 4xx or 5xx response, so return a success code as quickly as possible and handle heavy processing asynchronously. ### What's the difference between 401 and 403? A `401 Unauthorized` means the request lacks valid authentication credentials — the client has not proven who they are. A `403 Forbidden` means the client is authenticated (the server knows who they are) but does not have permission to access the requested resource. In webhook terms, 401 usually means a bad or missing signature, while 403 means the webhook source is recognized but not allowed. ### Why am I getting 429 errors? A 429 means the server is rate-limiting your requests because you have exceeded the allowed number of requests in a given time window. To resolve this, implement exponential backoff in your retry logic: wait 1 second after the first failure, then 2 seconds, 4 seconds, and so on. Also check the `Retry-After` header, which many servers include to tell you exactly how long to wait.