SEO & Crawler Security

Robots.txt Parser & Validator

An interactive, client-side utility to parse, validate, and debug your robots.txt file. Real-time path testing against major search engine crawlers with custom wildcards support.

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Robots.txt Rules

0 lines parsed

Test URL Path

https://example.com

User-agent Crawler

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Awaiting Rules

Enter robots.txt rules on the left to start testing paths.

Evaluation Diagnostic

Block Match: -

Winning Rule: -

Matching Reason: -

How Robots.txt Matching Works

Crawlers examine your robots.txt directives and evaluate matching rules using a standard specificity-based priority system. Our parser adheres strictly to modern robot exclusion standards:

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Longest Rule Wins — If multiple directives match a target URL path, the rule with the longest matching character pattern takes precedence.
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Allow Over Disallow — If an Allow and a Disallow directive have the exact same length and both match, the Allow rule wins.
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User-Agent Specificity — A crawler only reads the single, most-specific block matching its name (e.g. Googlebot). If no block specifically matches, it falls back to the generic * block.
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Wildcards & Endings — * matches any sequence of characters, while $ anchors the path to match the exact end of the string.

Common Robots.txt Pitfalls

❌ Missing leading slashes

Writing Disallow: admin/ instead of Disallow: /admin/. This may fail to match correctly on many standard crawlers.

❌ Placing Crawl-delay inside Googlebot blocks

Googlebot ignores the Crawl-delay directive entirely. To limit crawl rates, use settings within the Google Search Console instead.

❌ Case Sensitivity Misunderstandings

Directives like Disallow: /private/ will NOT block crawlers from requests accessing /Private/ or /PRIVATE/.

Frequently Asked Questions

What is a robots.txt parser and validator?

A robots.txt parser and validator is an SEO tool that reads a website's robots.txt directives, analyzes them for syntax issues or invalid directives, and allows you to test whether specific URL paths are allowed or blocked for different search engine crawlers.

How does the interactive URL tester work?

You enter a relative path (like /admin/settings) and select a crawler (like Googlebot). The tool parses your rules, identifies the specific block matching that user-agent (falling back to * if needed), runs prefix and wildcard matching, and determines if the path is allowed or blocked.

Does this tool support wildcards and the $ symbol?

Yes! The parser fully supports the official robots.txt specifications, including * wildcards (matching zero or more characters) and the $ suffix (anchoring matches to the end of the URL path).

Is my robots.txt file secure and private?

Absolutely. The entire parsing, linting, and URL testing engine runs entirely client-side in your web browser. Your robots.txt rules and tested paths are never uploaded to any server or shared with third parties.