226 vs 200: IM Used vs OK
226 and 200 can look similar in logs, but they tell clients, crawlers, and API consumers different things.
| Aspect | 226 | 200 |
|---|---|---|
| Meaning | IM Used describes how the server processed the request and what the client should do next. | OK describes how the server processed the request and what the client should do next. |
| Typical use case | HTTP 226 IM Used indicates a success response outcome. | HTTP 200 OK indicates a success response outcome. |
| Caching/client behavior | Check cache headers and downstream behavior for 226. | Check cache headers and downstream behavior for 200. |
| SEO implications | Search crawlers interpret 226 according to success semantics. | Search crawlers interpret 200 according to success semantics. |
| API/backend impact | API clients may branch logic specifically on 226. | API clients may branch logic specifically on 200. |
When to use one vs the other
Use 226 when the response should communicate im used behavior; use 200 when ok is the accurate protocol signal.
A frequent mistake is swapping 226 and 200 for convenience; that causes client retry bugs, incorrect cache signals, and misleading monitoring data.
Decision summary: if user agents should receive the IM Used signal, return 226; if they should receive OK, return 200.
FAQ
What is the biggest difference between 226 and 200?
226 communicates IM Used, while 200 communicates OK. Choosing the right one keeps clients and intermediaries predictable.
Do 226 and 200 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 226 instead of 200?
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: 226 IM Used · 200 OK