301 vs 308: Moved Permanently vs Permanent Redirect
301 and 308 can look similar in logs, but they tell clients, crawlers, and API consumers different things.
| Aspect | 301 | 308 |
|---|---|---|
| Meaning | Moved Permanently 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 301 Moved Permanently indicates a redirection response outcome. | HTTP 308 Permanent Redirect indicates a redirection response outcome. |
| Caching/client behavior | Check cache headers and downstream behavior for 301. | Check cache headers and downstream behavior for 308. |
| SEO implications | Search crawlers interpret 301 according to redirect-codes semantics. | Search crawlers interpret 308 according to redirect-codes semantics. |
| API/backend impact | API clients may branch logic specifically on 301. | API clients may branch logic specifically on 308. |
When to use one vs the other
Use 301 when the response should communicate moved permanently behavior; use 308 when permanent redirect is the accurate protocol signal.
A frequent mistake is swapping 301 and 308 for convenience; that causes client retry bugs, incorrect cache signals, and misleading monitoring data.
Decision summary: if user agents should receive the Moved Permanently signal, return 301; if they should receive Permanent Redirect, return 308.
FAQ
What is the biggest difference between 301 and 308?
301 communicates Moved Permanently, while 308 communicates Permanent Redirect. Choosing the right one keeps clients and intermediaries predictable.
Do 301 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 301 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: 301 Moved Permanently · 308 Permanent Redirect