#541 · Developer Tool

Robots.txt Validator

Check a robots.txt file before publishing it at the root of a site. The validator separates user-agent groups, recognizes Allow and Disallow rules, checks Sitemap and Host values, and reports malformed or misplaced directives with line numbers. It also flags patterns that often cause accidental crawling blocks, including an empty user-agent and a site-wide Disallow rule. The analysis runs locally and does not fetch or test a live domain.

Developer Input

Web metadata input
Ad space

How to use this developer tool

  1. Paste the requested source text or load a local file.
  2. Set any comparison values or processing options shown below the input.
  3. Select the primary action or press Ctrl/Cmd + Enter.
  4. Review the diagnostics, then copy or download the output.

What this developer tool does

The report lists parsed groups and line-specific findings so you can distinguish syntax mistakes from intentional crawler policy.

Lines are parsed case-insensitively. Allow and Disallow belong to the active User-agent group; Sitemap and Host are accepted as global directives.

A valid file controls crawling preferences, not indexing guarantees or access security.

Example

Input

User-agent: *
Disallow: /private/
Allow: /private/help.html
Sitemap: https://example.com/sitemap.xml

Run the sample to see the exact report and metrics produced by the current implementation.

Use cases

  • Pre-deployment review of generated site files
  • Debugging crawler or link-preview configuration
  • Auditing metadata during a migration
  • Creating repeatable QA evidence for a release

Tips for reliable output

  • Paste the complete source when grouping or document context matters.
  • Use absolute public URLs unless the field explicitly accepts a path.
  • Retest after redirects, route rules, or locale mappings change.
  • Keep a deliberately invalid sample for regression checks.
  • Confirm the deployed result with the relevant external platform.

Processing details

Lines are parsed case-insensitively. Allow and Disallow belong to the active User-agent group; Sitemap and Host are accepted as global directives. The parser runs entirely in the current browser tab and returns copy-ready text plus structured exports when useful.

A valid file controls crawling preferences, not indexing guarantees or access security.

Frequently asked questions

Can I use this tool without uploading data?

Yes. Processing happens in your browser, and the page makes no request with the supplied input.

What happens when the input is malformed?

The Robots.txt Validator stops, displays an actionable error, and does not produce a misleading successful result.

Does the result guarantee search engine behavior?

No. The result checks the supplied markup or rules; crawlers and social platforms may apply additional policies and cached data.

Can I download the result?

Yes. Use Download for the primary output, or the CSV and JSON buttons when structured exports are available.

How should I test the result before deployment?

Run a representative valid sample and a deliberately invalid case, then verify the deployed public URL with the relevant crawler or platform tool.

Checks and output

AreaBehavior
InputProcessed locally
ErrorsReported without silent correction
ExportCopy, download, and structured data when available

Web Meta & Server Files

Inspect crawler directives, sitemap files, canonical URLs, localized alternates, and social metadata.

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