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 | HTTP 226 — IM Used | HTTP 200 — OK |
|---|---|---|
| Definition | IM Used describes how the server processed the request and what the client should do next. | The server successfully processed the request and is returning the requested resource or result. This is the most common status code in normal web traffic. |
| Plain-language summary | HTTP 226 IM Used indicates a success response outcome. | The server received the request, processed it, and is returning the result. This is the expected response for most GET, POST, PUT, and PATCH requests. If you see 200 in your logs, the connection and request lifecycle completed without error — though the business logic in the response body may still contain application-level errors depending on the API design. |
| When to use | HTTP 226 IM Used indicates a success response outcome. | Return 200 when the request succeeded and there is a body to return. For successful creation use 201. For successful deletion or updates with no body use 204. Avoid wrapping error messages inside 200 responses — it breaks client error handling and monitoring dashboards. |
| Client behavior | Client handles 226 according to success semantics. | Clients display the response body as-is. Browsers render the page. API clients parse the JSON body. No retry is attempted. If caching headers are present, the response may be stored. |
| Caching behavior | See 226 caching spec. | Cacheable by default if Cache-Control, Expires, or Last-Modified headers are present. Without explicit cache headers, client behavior varies. Set Cache-Control: no-store for dynamic API responses, or appropriate max-age for stable resources. |
| SEO / crawler impact | Search crawlers interpret 226 (success) for indexation and link equity accordingly. | Search crawlers interpret 200 (success) for indexation and link equity accordingly. |
| API / backend impact | API clients branching on 226 expect IM Used semantics. | API clients branching on 200 expect OK semantics. |
| Safe to retry? | Only after fixing the underlying cause | Only after fixing the underlying cause |
Common real-world scenarios
When you see HTTP 226
226 appears in production when: Normal protocol behavior.
When you see HTTP 200
High-volume 200s are normal. Watch for latency spikes on 200 responses — they indicate slow processing before the successful response. Alert on p99 latency, not just 5xx rate. Application errors returned inside 200 bodies (common in older RPC-style APIs) are invisible to standard APM dashboards unless you parse the body.
Decision rule
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.
Use 226 when the correct protocol signal is IM Used. Use 200 when the correct signal is OK. Returning either code for the wrong reason breaks client expectations, cache behavior, and monitoring accuracy.
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.
Full guides
HTTP 226 IM Used — full guide · HTTP 200 OK — full guide · All comparisons · HTTP 226 status reference · HTTP 200 status reference