Changelog

v5.0.1 — Aug 21, 2026

@kubb/adapter-oas

Bug Fixes

• Fix an OpenAPI 3.1 multi-type array collapsing to one type when paired with format. type: ["null", "integer", "string"], format: "int32" generated integer | null, dropping string. The multi-type rule now runs before format, so each type parses on its own. (#3916, 3d0098c)
• Fix an OpenAPI 3.1 multi-type array dropping its other types when null came first. type: ["null", "string"] generated null instead of string | null, while type: ["string", "null"] generated the right type, so the output depended on the order the types happened to be written in. The normalized type now takes the first non-null entry, and type: ["null"] stays a null schema. (#3912, 331558e)

@kubb/cli

Bug Fixes

• Bump verkit to 0.4.0 and @tmcp/transport-stdio to 0.5.0. (#3909, 77e95a7)

@kubb/kit

Bug Fixes

• Fix Url.toPath producing an invalid Express-style route for a hyphenated path parameter (e.g. {point-id} became :point-id). path-to-regexp treats a hyphen as ending the parameter name, so the generated MSW handler matched :point followed by a literal -id and rejected valid values. Url.toPath now camelCases the parameter name the same way Url.toTemplateString already does, so {point-id} becomes :pointId. (#3895, bf9bdc8)

Contributors

Thanks to everyone who contributed to this release:

@stijnvanhulle

v5.0.0

Kubb v5 rebuilds code generation around adapters, a universal AST, parsers, and storage, and generates code up to 5.4x faster than v4. Config gets shorter, generated client calls change shape, and plugins move to their own repo (kubb-labs/plugins).

Read the release blog post for the highlights, and the migration guide for the full, per-package breaking-change list and upgrade steps.

For prior releases, see GitHub Releases.