#548 · Developer Tool

Hreflang Tag Validator

Review hreflang link elements from a page head before they reach production. The validator extracts alternate links, checks language tag shape and casing, resolves relative URLs against the current page, and reports duplicate locales, duplicate targets, fragments, and missing self-reference. An optional rule requires x-default. The result covers what can be established from one document; reciprocal tags on remote language pages are intentionally left as a deployment check.

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 identifies errors within the supplied alternate cluster and summarizes its resolved locale-to-URL mapping.

Only link elements whose rel token contains alternate and that have hreflang are inspected. URLs are resolved with the current page as their base.

Reciprocal return links cannot be confirmed without fetching each alternate page, so test them separately after deployment.

Example

Input

<link rel="alternate" hreflang="en-US" href="https://example.com/en/">
<link rel="alternate" hreflang="ko-KR" href="https://example.com/ko/">
<link rel="alternate" hreflang="x-default" href="https://example.com/">

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

Only link elements whose rel token contains alternate and that have hreflang are inspected. URLs are resolved with the current page as their base. The parser runs entirely in the current browser tab and returns copy-ready text plus structured exports when useful.

Reciprocal return links cannot be confirmed without fetching each alternate page, so test them separately after deployment.

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 Hreflang Tag 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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