Installation

Add the package as a dependency:

npm install --save @trapi/swagger

Requirements

• Node.js ≥ 22
• TypeScript ≥ 5 — required through @trapi/metadata, which uses the compiler API at runtime.

@trapi/metadata is a direct dependency of @trapi/swagger, so installing swagger pulls it in transitively. Install it explicitly too if you want to import its types (Metadata, MetadataGenerateOptions) in your own code:

npm install --save @trapi/metadata

If you want @trapi/swagger to run metadata extraction itself (by passing MetadataGenerateOptions to generateSwagger), you also need a decorator mapping installed — a shipped preset (@trapi/preset-decorators-express or @trapi/preset-typescript-rest), or your own:

npm install --save @trapi/preset-decorators-express @decorators/express

Module Format

ESM-only. Same caveat as @trapi/metadata: set "type": "module" in your package.json or load via dynamic import() from CommonJS.

Verify

import { generateSwagger } from '@trapi/swagger';

const spec = await generateSwagger({
    version: 'v3',
    metadata: {
        entryPoint: 'src/controllers/**/*.ts',
        preset: '@trapi/preset-decorators-express',
    },
    data: { name: 'My API', version: '1.0.0' },
});

console.log(spec.openapi);  // '3.0.0'

Once that runs, continue to Generating a Spec.