103 vs 200: Early Hints vs OK
103 and 200 can look similar in logs, but they tell clients, crawlers, and API consumers different things.
| Aspect | 103 | 200 |
|---|---|---|
| Meaning | Early Hints 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 103 Early Hints indicates a informational response outcome. | HTTP 200 OK indicates a success response outcome. |
| Caching/client behavior | Check cache headers and downstream behavior for 103. | Check cache headers and downstream behavior for 200. |
| SEO implications | Search crawlers interpret 103 according to informational semantics. | Search crawlers interpret 200 according to success semantics. |
| API/backend impact | API clients may branch logic specifically on 103. | API clients may branch logic specifically on 200. |
When to use one vs the other
Use 103 when the response should communicate early hints behavior; use 200 when ok is the accurate protocol signal.
A frequent mistake is swapping 103 and 200 for convenience; that causes client retry bugs, incorrect cache signals, and misleading monitoring data.
Decision summary: if user agents should receive the Early Hints signal, return 103; if they should receive OK, return 200.
FAQ
What is the biggest difference between 103 and 200?
103 communicates Early Hints, while 200 communicates OK. Choosing the right one keeps clients and intermediaries predictable.
Do 103 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 103 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: 103 Early Hints · 200 OK