102 vs 202: Processing vs Accepted
102 and 202 can look similar in logs, but they tell clients, crawlers, and API consumers different things.
| Aspect | 102 | 202 |
|---|---|---|
| Meaning | Processing describes how the server processed the request and what the client should do next. | Accepted describes how the server processed the request and what the client should do next. |
| Typical use case | HTTP 102 Processing indicates a informational response outcome. | HTTP 202 Accepted indicates a success response outcome. |
| Caching/client behavior | Check cache headers and downstream behavior for 102. | Check cache headers and downstream behavior for 202. |
| SEO implications | Search crawlers interpret 102 according to informational semantics. | Search crawlers interpret 202 according to success semantics. |
| API/backend impact | API clients may branch logic specifically on 102. | API clients may branch logic specifically on 202. |
When to use one vs the other
Use 102 when the response should communicate processing behavior; use 202 when accepted is the accurate protocol signal.
A frequent mistake is swapping 102 and 202 for convenience; that causes client retry bugs, incorrect cache signals, and misleading monitoring data.
Decision summary: if user agents should receive the Processing signal, return 102; if they should receive Accepted, return 202.
FAQ
What is the biggest difference between 102 and 202?
102 communicates Processing, while 202 communicates Accepted. Choosing the right one keeps clients and intermediaries predictable.
Do 102 and 202 have SEO or caching impact?
Yes. Search engines and caches interpret status classes differently. Use each code according to its semantics to avoid accidental indexing, stale responses, or crawl inefficiency.
Can APIs safely return 102 instead of 202?
Only when it matches contract semantics. API clients often branch logic by exact code, so swapping them can break retries, auth handling, or user-facing errors.
Related guides: 102 Processing · 202 Accepted