HTTP status code 202 “Accepted” indicates that the server has received the request and is processing it, but has not yet completed the operation. This status code informs the client that the request has been accepted, but the outcome is not yet known, or it may take a long time to complete. This differs from status code 200, which indicates that the request has been successfully completed.
The 202 status code is typically used for asynchronous operations, where the server has begun processing the request but does not want the client to wait. Instead, it allows the client to continue with other tasks. In this case, the server returns a 202 status code and may inform the client of the processing result at a later time through other means (such as notifications or polling).
Common Scenarios for 202 Responses:
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Large Data Processing: When a request requires significant computation or data processing on the server, it can immediately return a 202 status code, indicating that the request has been accepted but processing is not complete.
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Task Queues: The server can place the request in a background task queue and return a 202 status code immediately, while the actual processing may occur asynchronously in the background.
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Scheduled Operations: For operations that need to be executed at a specific time, the server can return a 202 status code immediately and perform the operation at the designated time.
Example of a 202 Response:
HTTP/1.1 202 Accepted
Content-Type: text/plain
Content-Length: 15
Request accepted.
In this example, the server returns a brief message “Request accepted,” indicating that the request has been accepted, but processing is not yet complete. The response body may contain additional information, but this is generally optional.
Sometimes, the server may also include a Retry-After header in the response, indicating how long the client should wait before checking the status of the request again, or when the processing may be completed.