HTTP 102 Processing

What It Means

The HTTP 102 Processing status code is an interim response used to inform the client that the server has received the complete request and is working on it. This prevents the client from timing out while waiting for a response to a long-running request.

Origin

This status code is defined in RFC 2518 as part of the WebDAV (Web Distributed Authoring and Versioning) specification. It's specifically designed for operations that may take a significant amount of time to complete.

When It's Used

Large file operations: Copying or moving large files on a WebDAV server
Complex queries: Operations that require significant server-side processing
Batch operations: Processing multiple resources in a single request

Example Scenario

# Client initiates large COPY operation
COPY /documents/large-folder HTTP/1.1
Host: webdav.example.com
Destination: /backup/large-folder

# Server sends interim response
HTTP/1.1 102 Processing

# ... server continues processing ...

# Server sends final response
HTTP/1.1 201 Created
Location: /backup/large-folder

Key Points

This is an interim response, not a final one
A final status code (2xx, 4xx, 5xx) will follow
Primarily used in WebDAV contexts, rarely seen in standard HTTP
Helps prevent client-side timeouts during long operations
Deprecated in HTTP/2 and HTTP/3 (use different mechanisms)

Modern Alternatives

For modern APIs, consider these patterns instead:

202 Accepted + polling: Return immediately, client polls for status
Webhooks: Notify client when processing completes
WebSockets: Push progress updates to the client