---
title: default_locale
slug: Mozilla/Add-ons/WebExtensions/manifest.json/default_locale
page-type: webextension-manifest-key
tags:
  - Add-ons
  - Extensions
  - WebExtensions
browser-compat: webextensions.manifest.default_locale
---

{{AddonSidebar}}

<table class="fullwidth-table standard-table">
  <tbody>
    <tr>
      <th scope="row">Type</th>
      <td><code>String</code></td>
    </tr>
    <tr>
      <th scope="row">Mandatory</th>
      <td>
        Contingent: must be present if the _locales subdirectory is present,
        must be absent otherwise.
      </td>
    </tr>
    <tr>
      <th scope="row">Example</th>
      <td><pre class="brush: json">"default_locale": "en"</pre></td>
    </tr>
  </tbody>
</table>

This key must be present if the extension contains the \_locales directory, and must be absent otherwise. It identifies a subdirectory of \_locales, and this subdirectory will be used to find the default strings for your extension.

See [Internationalization](/en-US/docs/Mozilla/Add-ons/WebExtensions/Internationalization).

## Example

```json
"default_locale": "en"
```

## Browser compatibility

{{Compat}}


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Type	`String`
Mandatory	Contingent: must be present if the _locales subdirectory is present, must be absent otherwise.
Example	"default_locale": "en"