Convert Extension JSON to Qt Linguist online

Upload a Browser extension messages.json file and download it as Qt Linguist .ts. Translation keys, plurals and placeholders are preserved. Free, no account needed.

Pick the source format or let the converter detect it from the file.

Used when the source format holds one language per file. Also used as the source language for XLIFF output.

Choose the format you want to download.

Qt Linguist .ts

XML translation sources used by Qt Linguist and lrelease. Messages are grouped by context and compiled to binary .qm files at build time.

One file per language. Format documentation

Need it the other way round? Convert Qt Linguist to Extension JSON.

From: Browser extension messages.json

The _locales/xx/messages.json format used by Chrome, Firefox and Edge extensions. Every key holds a message and an optional description for translators.

Used by: Chrome extensions, Firefox add-ons, Edge extensions. One language per file. Read the Extension JSON format guide.

{ "appName": { "message": "My Extension", "description": "The name of the extension" }, "greeting": { "message": "Hello, $USER$!", "description": "Greets the user", "placeholders": { "user": { "content": "$1", "example": "John" } } } }
{
  "appName": {
    "message": "My Extension",
    "description": "The name of the extension"
  },
  "greeting": {
    "message": "Hello, $USER$!",
    "description": "Greets the user",
    "placeholders": {
      "user": {
        "content": "$1",
        "example": "John"
      }
    }
  }
}

To: Qt Linguist .ts

XML translation sources used by Qt Linguist and lrelease. Messages are grouped by context and compiled to binary .qm files at build time.

Used by: Qt, QML, C++. One language per file. Read the Qt Linguist format guide.

<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE TS> <TS version="2.1" language="pl"> <context> <name>AboutPage</name> <message> <source>Author</source> <translation>Autor</translation> </message> <message> <source>Website</source> <translation>Strona WWW</translation> </message> <message> <source>Version</source> <translation>Wersja</translation> </message> <message> <source>Found %n files</source> <translation> <numerusform>Znaleziono %n plik</numerusform> <numerusform>Znaleziono %n pliki</numerusform> <numerusform>Znaleziono %n plików</numerusform> </translation> </message> </context> </TS>
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE TS>
<TS version="2.1" language="pl">
    <context>
        <name>AboutPage</name>
        <message>
            <source>Author</source>
            <translation>Autor</translation>
        </message>
        <message>
            <source>Website</source>
            <translation>Strona WWW</translation>
        </message>
        <message>
            <source>Version</source>
            <translation>Wersja</translation>
        </message>
        <message>
            <source>Found %n files</source>
            <translation>
                <numerusform>Znaleziono %n plik</numerusform>
                <numerusform>Znaleziono %n pliki</numerusform>
                <numerusform>Znaleziono %n plików</numerusform>
            </translation>
        </message>
    </context>
</TS>

How to convert Extension JSON to Qt Linguist

  1. Drop your .json file into the converter above, or paste its content.
  2. Confirm the language of the file. It is guessed from the file name, for example de.json or messages_pt-BR.properties.
  3. Click Convert. You get one .ts file per language.
  4. Preview the result, copy it or download the files.

What changes between Extension JSON and Qt Linguist

  • Keys, texts, plural forms and placeholders are mapped one to one. Comments and descriptions are kept when both formats support them.

Convert and translate in one place

If you need the Qt Linguist file in more languages, the fastest route is a free SimpleLocalize project: import the Extension JSON file, add languages, run auto-translation with DeepL, Google Translate, OpenAI, Claude or Gemini, and download the result as Qt Linguist. The CLI does the same from CI with upload and download commands, so the conversion becomes part of your build. See also translating Extension JSON files.

Frequently asked questions

Is the converter free?

Yes. There is no signup and no limit on the number of conversions beyond a few requests per second.

Are my files stored?

No. The file is parsed in memory, converted and returned in the same request. Nothing is written to disk or a database.

What about plurals and placeholders?

Plural forms are normalized to ICU message syntax and written back in the native form of Qt Linguist. Placeholders are kept, and Apple and Android specific syntax is translated between platforms. Read more in the pluralization guide.

Translate your Qt Linguist files

  • Import Extension JSON or Qt Linguist files into a free project
  • Auto-translate with DeepL, Google, OpenAI, Claude or Gemini
  • Download in any of the supported formats or publish to the CDN
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