Langbly Translate - GitHub Action

Automatically translate your JSON/YAML locale files and Markdown docs in CI/CD. Powered by Langbly, a context-aware translation API that's compatible with Google Translate v2.

Features

• JSON & YAML support - Nested and flat key structures (i18next, react-intl, Rails, etc.)
• Markdown docs - Translates body content while preserving frontmatter
• Placeholder preservation - {name}, %s, {{count}}, $t(key) are never translated
• Incremental translation - Only translates new or changed keys, preserving manual edits
• Multiple target languages - Translate to any number of languages in a single run
• Dry-run mode - Preview what would be translated before making changes
• Pull request support - Optionally create a PR with the translations

Quick Start

name: Translate

on:
  push:
    branches: [main]
    paths:
      - 'locales/en.json'

jobs:
  translate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: langbly/translate@v1
        with:
          api-key: ${{ secrets.LANGBLY_API_KEY }}
          source-language: en
          target-languages: fr,de,es,nl
          files: locales/en.json
          output-pattern: 'locales/{lang}.json'

      - uses: stefanzweifel/git-auto-commit-action@v5
        with:
          commit_message: 'Update translations'

Inputs

Input	Required	Default	Description
api-key	Yes	-	Your Langbly API key (get one free)
source-language	Yes	en	Source language code (ISO 639-1)
target-languages	Yes	-	Comma-separated target languages (e.g., fr,de,es,nl)
files	Yes	-	Glob pattern for source files (e.g., locales/en.json)
output-pattern	Yes	-	Output path with {lang} placeholder (e.g., locales/{lang}.json)
format	No	auto	File format: json, yaml, markdown, or auto
create-pr	No	false	Create a pull request with the translations
dry-run	No	false	Preview what would be translated

Outputs

Output	Description
files-translated	Number of files written
characters-used	Total source characters sent to the API

Examples

Translate JSON locale files

The most common use case. When your English locale file changes, translate it to all target languages:

- uses: langbly/translate@v1
  with:
    api-key: ${{ secrets.LANGBLY_API_KEY }}
    source-language: en
    target-languages: fr,de,es,nl,ja,ko,zh
    files: locales/en.json
    output-pattern: 'locales/{lang}.json'

Translate YAML locale files

Works with Rails-style YAML locale files:

- uses: langbly/translate@v1
  with:
    api-key: ${{ secrets.LANGBLY_API_KEY }}
    source-language: en
    target-languages: fr,de,nl
    files: config/locales/en.yml
    output-pattern: 'config/locales/{lang}.yml'

Translate Markdown documentation

Translate your docs site (Docusaurus, Hugo, Jekyll, etc.):

- uses: langbly/translate@v1
  with:
    api-key: ${{ secrets.LANGBLY_API_KEY }}
    source-language: en
    target-languages: fr,de
    files: 'docs/en/**/*.md'
    output-pattern: 'docs/{lang}/**/*.md'
    format: markdown

Dry run (preview changes)

See what would be translated without writing any files:

- uses: langbly/translate@v1
  with:
    api-key: ${{ secrets.LANGBLY_API_KEY }}
    source-language: en
    target-languages: fr,de
    files: locales/en.json
    output-pattern: 'locales/{lang}.json'
    dry-run: true

Create a pull request

Automatically create a PR with the translations for review:

- uses: langbly/translate@v1
  with:
    api-key: ${{ secrets.LANGBLY_API_KEY }}
    source-language: en
    target-languages: fr,de,nl
    files: locales/en.json
    output-pattern: 'locales/{lang}.json'
    create-pr: true
  env:
    GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Placeholder Preservation

The following placeholder formats are automatically protected during translation:

Format	Example	Used By
{name}	Hello, {name}!	i18next, React Intl, FormatJS
{{name}}	Hello, {{name}}!	Angular, Handlebars
%s, %d	%d items	printf, Android
%1$s	%1$s of %2$s	Android, Java
${var}	Hello, ${name}	Template literals
$t(key)	$t(common.yes)	i18next nested

Incremental Translation

The action compares your source file with existing translations. Only new keys are sent to the API. This means:

• Manual edits are preserved - If you've manually adjusted a translation, it won't be overwritten
• Lower API usage - You only pay for what's new
• Faster runs - Less data to process

Pricing

Langbly offers a free tier with 500,000 characters per month. That covers most small to medium projects. See langbly.com for full pricing.

License

MIT