Paste or upload a robots.txt file, choose a crawler, test real URLs, and surface matched allow or disallow rules before a production crawl policy goes live.
robots.txt, then add one URL or path per lineKeep the left side focused on inputs. The verdict table, matched rule, and issue digest stay visible on the right without hiding the result below a tall intro.
Use this board to review user-agent groups, rule counts, and the top rule patterns before you publish a crawler policy or hand it to another teammate.
No directive audit yet. Run validation to inspect sitemap lines, host notes, crawl-delay values, unknown directives, and orphan rules.
The report summary will appear here after validation.
A robots txt validator is a pre-publish quality gate for the plain-text file that tells crawlers which areas of a site should be requested, skipped, or treated with special care. The file looks small, but small mistakes can create large crawl problems. One misplaced Disallow line can hide important pages, one malformed sitemap line can remove a discovery hint, and one rule placed before any User-agent block can confuse the intent of the whole file. Those errors often reach production because the file feels too simple to deserve a serious review process.
That is why a useful robots txt validator needs to do more than count directives. It should answer the practical questions that matter before release: which crawler group matched, which rule actually won, whether the file contains risky structure issues, and whether the specific paths you care about are allowed or blocked. If the page only prints a few warnings without path testing, the user still has to guess how the file behaves in the real workflow that matters.
This ToolPortal page is built around that narrower, higher-value job. It keeps the analysis local in the browser, lets you paste or upload a draft robots.txt file, supports multiple URL or path tests, and shows the strongest matched rule for each verdict. That makes it useful for technical SEO reviews, staging-to-production release checks, and fast QA when a site owner or developer wants an answer now rather than a long explanation-first article.
“Calculate” in this context means estimating whether a robots.txt file is safe enough to publish without hiding the wrong URLs or sending confusing signals to crawlers. The first input is group structure. Every Allow or Disallow rule should live under a clear User-agent block. If rules appear before any crawler group, the file is already risky because the intent is unclear and the release reviewer may assume the parser will interpret it more generously than it actually should.
The second input is rule precedence. Crawlers do not simply stop at the first line that looks relevant. They choose the group that best matches their user-agent and then apply the strongest matching rule for the URL path being tested. That is why matched-rule visibility matters. If a path is blocked, you need to know exactly which rule caused it and whether an Allow line should outrank the broader Disallow pattern. A validator that hides that logic forces the user to debug by hand.
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. Once those layers are visible, the release decision becomes practical: fix errors before publish, review warnings that change crawler intent, and then rerun the same high-risk URLs before the file goes live.
A site owner tests /checkout/, /checkout/help/, and a product URL before deploying a new robots file. The validator shows that the help page is allowed, but the broader checkout path stays blocked for the selected crawler.
A developer leaves a staging Disallow rule in the file and the test matrix immediately shows the exact paths that would disappear from crawl once the draft reaches production.
A reviewer pastes a draft robots file and sees that the sitemap line is not an absolute URL. The warning is small, but catching it early keeps the final release cleaner and more portable.
Many robots.txt tools technically “work,” but they still underperform in real release workflows. They may flag a typo or tell you that a file contains a few groups, yet still leave the core question unanswered: what happens to the URLs I care about for the crawler I care about? That is too thin for launch reviews, technical SEO audits, and emergency rollback checks. Users need the practical verdict and the reasoning behind it.
This page is designed to close that gap. The first screen keeps the inputs on the left and a visible verdict board on the right. The test table shows whether each path is allowed or blocked. The issue cards surface structural risks immediately. The group board and directive audit below the fold carry the deeper diagnostics that matter when you need to hand the file to another teammate, explain a crawl bug, or document what changed between two drafts.
The result is still intentionally scoped. This is not a remote crawler simulator or a replacement for large-scale log analysis. It is a focused, practical validator for the moments when you need to understand the file quickly, catch obvious release risk, and make the next action clear without reading through a generic article that never reaches the actual rule logic.
It checks robots.txt structure, user-agent groups, sitemap lines, host and crawl-delay notes, plus URL-level allow or block verdicts for the crawler you choose.
Yes. You can paste one path or full URL per line, choose a crawler, and the tool will show 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, so the robots.txt content stays in your session unless you choose to copy it elsewhere.