Changelog

3.69.1

(internal): Regenerate older IR types with new TypeScript SDK generator.

3.69.0

(feat): [Beta] Add fern docs md generate command for generating MDX documentation from library source code. This feature requires a libraries configuration in docs.yml. The command is in beta and may change in future releases.

3.68.1

(fix): Fix grouped multi-API environment server handling to preserve defaultUrl, urlTemplate, and variables metadata when merging multiple OpenAPI specs with group-multi-api-environments: true. Previously, server URL templating metadata was silently dropped during the merge, causing generated SDKs to use malformed template-substituted URLs as defaults. Also fixes API name extraction for grouped base URL keys to use the clean x-fern-default-url value instead of the variable-substituted URL.

3.68.0

(feat): Add folder-title-source global setting in docs.yml under settings. When set, this value is used as the default title-source for all folder navigations that do not explicitly specify their own title-source. This allows configuring frontmatter or filename as the default title derivation strategy for all folders in one place.

3.67.1

(fix): Fix title-source: frontmatter in folder navigation to correctly pass the setting through to buildNavigationForDirectory. Previously, the title-source option was ignored when expanding folder configurations, so page titles and sidebar titles always derived from file names. Now, when title-source: frontmatter is set, page titles and the folder section title use the frontmatter title field.

3.67.0

(feat): Adds schema name and title collision detection for OpenAPI/AsyncAPI specs. When title-as-schema-name is enabled and multiple schemas share the same title, fern check now reports an error identifying the conflicting schemas. To opt in to automatic resolution, set resolve-schema-collisions: true in your generators.yml settings under api/specs:

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api:
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  specs:
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    - asyncapi: asyncapi.yml
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      settings:
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        title-as-schema-name: true
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        resolve-schema-collisions: true

When enabled, colliding titles are disambiguated with a numeric suffix (e.g. OpenAI2) and a warning is emitted instead of an error.

(fix): Run OSS validation rules (e.g. schema title collision detection) during fern generate, not just during fern check. This ensures validation errors are surfaced before generation proceeds.

3.66.0

(feat): Add support for server URL templating in multi-URL environments. The Fern definition schema now supports url-templates, default-urls, and variables fields on MultipleBaseUrlsEnvironmentSchema, enabling SDKs to expose server variables as constructor parameters with runtime URL interpolation.

3.65.1

(fix): Fix fern check --strict-broken-links was not validating markdown files referenced by sections with paths.

3.65.0

(feat): Add --generator option to fern generate to run a specific generator by name. Filters within the resolved group (from --group or default-group) to only run the specified generator.