102 Processing
Defined in WebDAV (RFC 2518), this response tells the client that the server is still processing a request that will take some time. It prevents the client from timing out prematurely. Not commonly used in standard web applications.
What can I do?
- No action needed — this is an informational or success response, not an error.
How to debug & fix
- Increase client timeout settings if operations legitimately take long
- Consider WebSockets or Server-Sent Events for real-time progress updates instead
- Set up proper Nginx/proxy read_timeout values
- Prefer Server-Sent Events (SSE) or WebSockets for live progress in modern apps — 102 is rarely worth implementing.
Code Example
// Rarely used in practice; for WebDAV or long operations:
res.writeHead(102); // interim
res.flushHeaders();
await doLongOperation();
res.writeHead(200);
res.end('Done');Related Status Codes
How HTTP Status Codes Work
Every HTTP response carries a three-digit status code that tells the client — browser, API consumer, or search-engine crawler — exactly what happened. The first digit defines the class: 1xx informational (request in progress), 2xx success, 3xx redirection, 4xx client error (bad request, missing auth, not found), and 5xx server failure.
Status codes are standardised in RFC 9110 (HTTP Semantics, 2022). Extensions like WebDAV (RFC 4918) and rate-limit headers (RFC 6585) added codes beyond the core set. When a client receives an unrecognised code, the rule is to treat it as the generic x00 of its class.
Why the Right Code Matters
Semantically correct codes help search engines index accurately (301 passes link equity; 410 removes pages faster than 404), allow API clients to implement correct retry logic (429 + Retry-After, 503 + Retry-After), and let monitoring systems distinguish bugs (500) from load issues (503) from auth failures (401/403).
Looking up a different status code? The full reference covers all HTTP codes with causes, fix guides, and copyable code examples for Node.js and Python.
Browse the full HTTP Status Code reference →