Paste a robots.txt file, choose Googlebot, Bingbot, GPTBot, or another crawler, then test URLs to see which pages are allowed or blocked before you publish the file.
Validation Result
The result board shows which URLs can be crawled, which URLs are blocked, and which robots.txt rule caused each verdict.
The page checks user-agent groups, sitemap lines, structure issues, and whether the selected crawler can access the paths you care about.
Use the clean sample for a normal rule matrix or the risky sample for malformed lines and rule-placement mistakes.
Direct Answer
A robots.txt validator checks whether a robots.txt draft is structurally valid and whether specific URLs are allowed or blocked for a selected crawler. The useful answer is not only whether the file parses. The real question is which user-agent group matched, which allow or disallow rule won, and whether a production URL would be crawlable after release.
AI Answer Summary
Paste the exact robots.txt draft, choose Googlebot, Bingbot, GPTBot, Applebot, or a custom crawler, and test high-risk paths before deploy.
The page shows the winning allow or disallow rule with the line number, so broad blocks and specific exceptions are easier to explain.
Review sitemap lines, host notes, crawl-delay values, unknown directives, and duplicate hints before the file goes live.
Use GPTBot, Applebot, or a custom user-agent to see whether the crawler-specific group actually matches your intended policy.
Decision Guide
| Use case | Use it when | Skip or add another tool when |
|---|---|---|
| Pre-production crawl rule review | You need to test a draft against 3 to 20 important paths before a deploy. | You need full server log analysis or crawl-budget modeling across millions of URLs. |
| AI crawler access checks | You want to see whether GPTBot, Applebot, or another named crawler is matched by a specific group. | You need WAF rules, contractual bot controls, or paywalled content enforcement. |
| Sitemap and directive cleanup | You need quick warnings for malformed sitemap lines, duplicate hints, Host notes, Crawl-delay values, or unknown directives. | You need Google Search Console indexing status, live fetches, or historical sitemap discovery data. |
Publishing Checklist
Always include the homepage, one money page, one intentionally blocked private path, one sitemap-discovered path, and one path with a query string.
Validate both the default User-agent: * policy and any crawler-specific group that could override it for Googlebot, Bingbot, or AI crawlers.
Use absolute sitemap URLs, avoid duplicate sitemap lines, and keep sitemap hints separate from temporary staging or migration rules.
Common Mistakes
A short rule such as Disallow: /app may block more than the release owner expected. Test exact production URLs, not only folder names, so accidental overlaps are visible before deployment.
Some directives are crawler-specific or ignored by many crawlers. Treat unknown directives, Host lines, and Crawl-delay values as review prompts instead of universal controls.
A broad block can be correct, but important exceptions need specific Allow rules. The matched-rule table shows whether the exception actually wins for the selected path.
Review Workflow
Start with the URLs that matter most to the business. A useful test set usually includes the homepage, one category or collection page, one product or conversion page, one search or filtered URL, one intentionally private path, and one sitemap URL. If the file was created during a migration, also test old redirected paths and any folders that changed names.
Next, run the same paths against more than one crawler. The default User-agent: * group may look safe while a crawler-specific group blocks images, AI crawlers, ads bots, or a search engine crawler. Testing only one user-agent can miss the exact group that will affect a later workflow.
Finally, copy the validation report into the release note or pull request. The report gives reviewers a short record of the source, crawler, groups, blocked URLs, flags, and matched rules. That makes a robots.txt change easier to approve and easier to roll back if a crawl issue appears later.
How It Works
The validator starts with group structure. Every Allow or Disallow rule should live under a clear User-agent block. Rules before a crawler group are risky because the intended scope is unclear and release reviewers may assume the parser will behave more generously than it should.
The second input is rule precedence. Crawlers do not simply stop at the first relevant line. They choose the best matching user-agent group and then apply the strongest matching rule for the URL path. That is why matched-rule visibility matters. If a path is blocked, the report should show exactly which line caused it.
The third input is directive quality. Sitemap lines should usually be absolute URLs, unknown directives should be reviewed instead of assumed, and special lines such as Host or Crawl-delay need context because not every crawler treats them the same way.
The boundary is deliberate. This page is a focused pre-release validator, not a full crawler, log analyzer, or indexing monitor. Use it to catch obvious policy mistakes quickly, then pair it with platform data when a business-critical page disappears from search.
Worked Examples
A site owner tests /checkout/, /checkout/help/, and a product URL before deploying a new robots file. The validator shows that help is allowed while checkout stays blocked.
A developer leaves a staging Disallow rule in the file and the test matrix immediately shows the paths that would disappear from crawl after release.
A reviewer pastes a draft and sees that the sitemap value is not an absolute URL. The warning is small, but it keeps the final release cleaner and more portable.
FAQ
It checks robots.txt structure, user-agent groups, sitemap lines, host and crawl-delay notes, unknown directives, plus URL-level allow or block verdicts for the crawler you choose.
Yes. Paste one path or full URL per line, choose a crawler, and the validator shows whether each path is allowed or blocked by the matched rule set.
No. This version keeps processing local in your browser. Paste or upload the file content, then run the tests on-page.
It follows common robots.txt matching logic and longest-match rule precedence, but it is still a practical browser validator rather than an official crawler simulator.
A page can be blocked or allowed by the strongest matching rule, not simply the first rule you see. Surfacing the matched rule helps you debug accidental crawl blocks faster.
No. Validation runs locally in your browser session unless you choose to copy the report or submit feedback.