v3/languages changelog

Changes and planned updates to the v3/languages endpoints during the beta period.

These endpoints are in BETA. We will try to announce breaking changes here before they land, but cannot guarantee advance notice. Do not use these endpoints in production.

Changes since the initial beta release

This section lists dated changes to the API since the initial beta release.

5 May 2026

Breaking: renamed product to resource — the product query parameter on GET /v3/languages has been renamed to resource. The /v3/languages/products endpoint has been renamed to /v3/languages/resources. Update all calls accordingly.

Breaking: features array replaced by object — the features property on language objects has changed from an array of strings to an object (dictionary). Each key is a feature name; the value is an object with at least a status field.

Instead of:

{
  "lang": "de",
  "features": ["formality", "tag_handling"]
}

the following schema is used:

{
  "lang": "de",
  "features": {
    "formality": {"status": "stable"},
    "tag_handling": {"status": "stable"}
  }
}

To check whether a feature is supported, check that the key exists in the features object.

New: language status field — language objects now include a status field indicating availability:

{
  "lang": "de",
  "status": "stable",
  "features": { ... }
}

Possible values: "stable", "beta", "early_access".

New: include query parameter — GET /v3/languages now accepts an include query parameter. By default (no parameter), only stable languages and features are returned.

Value	Effect
beta	Includes languages and features in beta, in addition to stable
external	Includes features that rely on third-party service providers

Values are composable via repeated parameters: ?include=beta&include=external.

Breaking: renamed custom_instructions feature to style_rules — the custom_instructions feature value returned by GET /v3/languages has been renamed to style_rules:

Old value	New value
custom_instructions	style_rules

This affects the features object returned per language and the feature list returned by GET /v3/languages/resources. Note: the custom_instructions parameter on the translate endpoint is not affected by this change.

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22 April 2026

Breaking: renamed required_on_source / required_on_target — the feature dependency flags on /v3/languages/products have been renamed:

Old name	New name
required_on_source	needs_source_support
required_on_target	needs_target_support

Semantics are unchanged. Update any code that reads these fields.

Breaking: removed endpoints from /v3/languages/products — the endpoints array has been removed from each product object. The applicable endpoints are still described in the documentation for each product.

New: auto_detection feature — a new auto_detection feature has been added across multiple products to indicate whether a language can be auto-detected as the source. This is a source-only feature (needs_source_support: true, needs_target_support: false).

17 April 2026

Removed: /v3/languages/exceptions — this endpoint has been removed. We no longer have any language pairs where feature support differs from what can be predicted from the individual language objects, so the endpoint had no data to return. Remove any calls to this endpoint; the per-language features objects from GET /v3/languages are sufficient to determine feature support for all pairs.

19 March 2026

Initial beta release.

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Possible additions

These are under consideration and may or may not land before GA.

• native_name field on language objects — the language’s name in that language (e.g. "Deutsch" for German).

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Current beta state

For the current API contract, see the overview and the auto-generated reference pages linked there.