303 vs 308: See Other vs Permanent Redirect
303 and 308 can look similar in logs, but they tell clients, crawlers, and API consumers different things.
| Aspect | 303 | 308 |
|---|---|---|
| Meaning | See Other describes how the server processed the request and what the client should do next. | Permanent Redirect describes how the server processed the request and what the client should do next. |
| Typical use case | HTTP 303 See Other indicates a redirection response outcome. | HTTP 308 Permanent Redirect indicates a redirection response outcome. |
| Caching/client behavior | Check cache headers and downstream behavior for 303. | Check cache headers and downstream behavior for 308. |
| SEO implications | Search crawlers interpret 303 according to redirect-codes semantics. | Search crawlers interpret 308 according to redirect-codes semantics. |
| API/backend impact | API clients may branch logic specifically on 303. | API clients may branch logic specifically on 308. |
When to use one vs the other
Use 303 when the response should communicate see other behavior; use 308 when permanent redirect is the accurate protocol signal.
A frequent mistake is swapping 303 and 308 for convenience; that causes client retry bugs, incorrect cache signals, and misleading monitoring data.
Decision summary: if user agents should receive the See Other signal, return 303; if they should receive Permanent Redirect, return 308.
FAQ
What is the biggest difference between 303 and 308?
303 communicates See Other, while 308 communicates Permanent Redirect. Choosing the right one keeps clients and intermediaries predictable.
Do 303 and 308 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 303 instead of 308?
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: 303 See Other · 308 Permanent Redirect