Requirements

Package	Role
next	Peer dependency — App Router only.
react	Peer dependency (matches Next.js's own requirement).
class-validator, class-transformer	Required for @Body() DTO validation.
class-validator-jsonschema	Required only if you use generateOpenApiDocument().
swagger-ui-dist	Required only if you use createSwaggerUiHandler().

Every dependency beyond next/react is an optional peer dependency — install only the ones the features you use actually need. npm install nextjs-nestapi alone will not pull any of them in for you.