What is a BCP-47 locale code?

BCP-47 is the standard for language tags used across the web and software. A tag combines subtags in the order language-script-region, such as zh-Hans-CN for Chinese written in simplified script as used in mainland China. Most everyday tags are just language-region, like en-US.

Why test with right-to-left locales?

Languages such as Arabic (ar) and Hebrew (he) are written right to left, which flips layout, alignment, and icon direction. Including RTL codes in your test set surfaces mirroring bugs that left-to-right-only testing never reveals.

When is a script subtag needed?

The script subtag is used when a language is written in more than one script, such as Chinese in Hans (simplified) or Hant (traditional), or Serbian in Latin versus Cyrillic. The tool includes these so you can test parsers that must handle the three-part form.

Does this upload anything?

No. The subtag lists and assembly logic are bundled into the page, so codes are generated entirely in your browser and nothing is uploaded.

Are the generated codes always valid?

The codes are assembled from real ISO 639 language, ISO 15924 script, and ISO 3166 region subtags in the correct BCP-47 order, so they are well-formed. The tool also marks which generated locales are right-to-left.

Random Locale Code Generator

A BCP-47 locale code is the standard language tag used throughout the web and software to identify a language and its regional or script variant. Tags follow the order language-script-region — for example en-US, fr-FR, or zh-Hans-CN. When building internationalized software you need a varied set of valid codes to test against. This tool generates random, well-formed BCP-47 codes, broken into their subtags, including right-to-left languages and script variants.

How it works

The generator keeps lists of real subtags: ISO 639 language codes, ISO 15924 script codes, and ISO 3166 region codes, with sensible pairings. When you generate:

It picks a language at random, then a region that the language is commonly used in.
For languages written in multiple scripts (such as Chinese or Serbian), it may add the appropriate script subtag, producing the three-part language-script-region form.
It assembles the subtags in correct BCP-47 order and flags whether the language is written right to left.

The result is a set of well-formed tags spanning two-part and three-part forms and both writing directions.

Tips and notes

Always include at least one RTL locale (ar, he, fa, ur) in your test matrix to catch layout-mirroring bugs.
Use the three-part script forms to verify your locale parser does not assume the simple language-region shape.
These codes are ideal for hreflang attributes, Accept-Language headers, and i18n fixture data.
Everything runs locally in your browser, so the tool works offline and uploads nothing.