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KUBB_UNSUPPORTED_FORMAT: Unsupported format

The KUBB_UNSUPPORTED_FORMAT diagnostic fires when a schema uses a format Kubb does not map to a specific type.

Code: KUBB_UNSUPPORTED_FORMAT Level: warning

A schema's format is not one Kubb maps to a specific type, so it falls back to the base type.

What happened ​

While walking the named component schemas, the OpenAPI adapter found a format it has no specific mapping for. Generation continues with the base type, for example string. This is a warning, not a failure. The adapter reports it on every run.

How to fix it ​

  • Use a format Kubb supports, or drop the format if the base type is enough.
  • Handle the custom format with a parser or plugin that maps it to the type you want.

Common causes ​

  • A vendor-specific format such as snowflake or money that has no built-in mapping.
  • A typo in a standard format, such as date-tine instead of date-time.

Example ​

petStore.yaml
components: schemas: Pet: type: object properties: id: type: string format: snowflake # falls back to string

Example output ​

Terminal
[KUBB_UNSUPPORTED_FORMAT]: Kubb does not map the format "snowflake" to a specific type, so it falls back to the base type. at: #/components/schemas/Pet/properties/id fix: Use a format Kubb supports, or handle "snowflake" with a custom parser or plugin. see: https://kubb.dev/docs/5.x/reference/diagnostics/kubb-unsupported-format

See also ​