#600 · Language & Unicode

Language Tag Validator

Check BCP 47 language tags before using them in HTML lang attributes, translation files, or Intl APIs. The validator canonicalizes well-formed tags, reports parsed language, script, and region subtags, and catches syntax the browser’s locale parser rejects.

Text Input

Language tags
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How to use this text tool

  1. Paste or type the text you want to process.
  2. Choose any options that apply to your target format.
  3. Select Validate Tags or press Ctrl/Cmd + Enter.
  4. Review the report, then copy or download the result.

What this tool does

Language Tag Validator turns hard-to-see text details into a readable result you can check before editing production content.

Intl.getCanonicalLocales performs standards-based structural validation and casing normalization. Intl.Locale then exposes recognized language, script, region, and extension fields.

A structurally valid tag is not proof that translations or locale data are available in a particular product.

Example

Load the sample to see a representative input. The result identifies or converts the relevant Unicode and locale details while leaving unrelated text in place.

Use cases

  • Checking localized UI copy before release
  • Cleaning data imported from documents or spreadsheets
  • Investigating text that compares or renders unexpectedly
  • Preparing reproducible notes for developers and translators

Tips for better output

  • Keep a copy of the original text.
  • Test the exact locale or target platform you plan to support.
  • Inspect warnings instead of applying bulk replacements blindly.
  • Use the downloadable report when sharing a finding.
  • Retest after changing normalization or formatting rules.

Processing details

Processing happens locally with built-in JavaScript Unicode and internationalization features. The report is generated from the text and options currently visible on the page.

A structurally valid tag is not proof that translations or locale data are available in a particular product.

Frequently asked questions

Does the Language Tag Validator send my text to a server?

No. The processing runs in your browser, so the pasted text is not uploaded by this page.

Can I use the result in a spreadsheet or localization file?

Yes. Copy the text output, download the report, or use the CSV and JSON exports when they appear.

Why can the result differ between browsers?

Unicode and locale data are updated over time. Browsers, fonts, and operating systems may support different versions.

Will this tool change my original text automatically?

No. Your input remains in the input box. Review the generated result before replacing source data.

What should I do with an invalid or suspicious result?

Check the reported code points or fields against the rules of the system that will consume the text.

Report fields

FieldMeaning
OutputThe processed text or inspection report
SummaryA count of the main findings
DetailsUnicode or locale-specific evidence