NestJS

Install

npm install @nestjs/swagger

Setup

Initialize the Swagger module in main.ts:

// main.ts
import { NestFactory } from '@nestjs/core'
import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger'
import { AppModule } from './app.module'

async function bootstrap() {
  const app = await NestFactory.create(AppModule)

  const config = new DocumentBuilder()
    .setTitle('My API')
    .setDescription('API description')
    .setVersion('1.0')
    .build()

  const document = SwaggerModule.createDocument(app, config)
  SwaggerModule.setup('api', app, document)

  // Also expose raw JSON
  app.getHttpAdapter().get('/openapi.json', (req, res) => {
    res.json(document)
  })

  await app.listen(3000)
}
bootstrap()

The spec is now available at:

http://localhost:3000/openapi.json

Add descriptions

Use decorators to enrich your spec:

import { ApiOperation, ApiParam, ApiTags } from '@nestjs/swagger'

@ApiTags('items')
@Controller('items')
export class ItemsController {
  @Get(':id')
  @ApiOperation({ summary: 'Get a single item', operationId: 'getItem' })
  @ApiParam({ name: 'id', type: Number })
  getItem(@Param('id') id: number) {
    return { id }
  }
}

Make it publicly accessible

Deploy your app or use a tunnel for local testing:

ngrok http 3000
# then use: https://<random>.ngrok.io/openapi.json

Verify

Visit /openapi.json in your browser. You should see a valid OpenAPI 3.x JSON document.

Paste this URL into Automiel’s import step.