Status Codes
Status codes in Prerender reflect how your content is being served or if there’s an issue with your setup. Understanding each code helps resolve content delivery and SEO issues.
Overview
When using Prerender, HTTP status codes are returned to bots like Googlebot, Bingbot etc., based on how your prerendered content is served. These codes signal whether bots can access your pages and directly impact how your site is crawled and indexed.
This guide explains what each status code means in the context of Prerender, how it impacts bot access, and what you should do next.
| Category | Status Code | What It Means | Impact | What to do |
|---|---|---|---|---|
|
Accessible (OK)
|
200 | Page loads, cached and served successfully | Crawlable but SEO could be weak | Improve content, metadata, links |
|
Blocked |
401 |
Requires authentication (pages are behind auth wall) | Bots cannot access | Remove auth or allow bots |
| 403 | Access is forbidden | Bots are blocked by server/CDN |
Check firewall or bot protection Whitelist Prerender.io IP address and user-agents |
|
| 409 | Request conflict (often bot protection) | Likely blocked by security rules | Review bot filtering rules | |
| 422 | Request rejected (bot challenge failure) | Bots fail validation checks | Disable CAPTCHA or JS challenges | |
| 429 |
Too Many Requests (trial render limit reached) |
Requests rejected due to hitting trial render limit |
Upgrade plan If you're on a paid plan and still see 429's, check firewalls, proxies, or rate-limiting rules |
|
| 404 | Page not found | Non-existent url |
If the url still exists in the site but Prerender returned 404: Check how the url was rewritten in CDN Analytics Check if the url matches any of the Ignored URL filters |
|
| 410 | Page permanently removed | Content intentionally gone | Confirm intent or redirect | |
| 520 | Unknown origin error | Unexpected server/CDN issue | Check origin logs | |
| 521 | Server down | Origin not reachable | Restart or fix server | |
| 525 | SSL handshake failed | HTTPS connection failed | Fix SSL/TLS config | |
| 530 | Site blocked/frozen | Hosting/CDN restriction | Review provider settings | |
|
Limited Access |
500 | Internal server error | Unstable access | Check backend errors |
| 502 | Bad gateway | Invalid upstream response | Check proxies/services | |
| 503 | Service unavailable | Server overloaded/down | Improve availability | |
| 504 | Gateway timeout | Rendering failed/timed out (firewall, rate-limit) | Optimize response time, fix JS errors, etc. (see more steps below) | |
| 301 | Permanent redirect | Indirect access | Ensure correct destination | |
| 302 | Temporary redirect | Indirect access | Use 301 if permanent | |
| 307 | Temporary redirect | Method-preserving redirect | Verify intent | |
| 308 | Permanent redirect | Redirect not followed by Prerender | Ensure target URL is Prerender-enabled to ensure bots will reach final URL | |
| 400 | Bad request | Invalid request format (malformed or unsupported request) | Check request handling |
What should be prioritized
- Fix Access Blocked issues (bots can’t reach your pages)
- Resolve Access Limited issues (unstable or indirect access)
- Improve Accessible pages (SEO optimization)
504 (Gateway Timeout)
This occurs when rendering the page fails due to timeouts or server-side issues.
Common causes include:
- Page renders blank (e.g., empty HTML like
<html><head></head><body></body></html>) - JavaScript errors block rendering
- Errors during rendering (e.g., failed API calls or script crashes)
- Checking if the page renders properly in a non-headless browser
- Looking for JavaScript errors in the console
- Ensuring you’re not rendering empty skeletons for bots
- Checking Rendering Timeout setting under the Advanced Setting to confirm how long Prerender waits before it returns a timeout error. You can configure this to up to 60s but the default is 20s.
It's worth noting that bots may retry when they receive a 504, but persistent issues can delay or prevent proper indexing.
504 errors are common and can be tied to rendering failures, not just access issues. Because they sometimes require deeper debugging (e.g., JavaScript or API issues), they include additional guidance.
Additional Tips / Best Practices
- Review the crawler visit logs in your Prerender Dashboard to identify which URLs returned specific codes.
- Verify your integration: Make sure your website/server is correctly forwarding requests to Prerender and that your token is valid and present.
- Use consistent and valid Prerender tokens across all environments.
- Ensure your page doesn’t rely on user interaction (scroll, click) to show core content needed for SEO.
- For pages with frequent redirects, make sure final destinations are also integrated with Prerender.
- Review blank or delayed content on the server. We recommend pre-loading essential content during SSR or hydration.
When to Contact Support
If error status codes persist and you’ve ruled out setup issues:
- Collect the full URL
- Include a screenshot of the status (from the dashboard or browser dev tools)
- Mention the status code and the conditions under which it appears
Then, reach out to us at support@prerender.io for assistance or you can contact us via the following:
- Log in to your Prerender dashboard
- Click 'Support' at the top right corner.
- Then, 'Contact Support'