Swagger is a tool to document your API using the OpenAPI specification. Nest has a dedicated module for Swagger, which you will be using shortly.

Get started by installing the required dependencies:

npm install --save @nestjs/swagger swagger-ui-express

Now open main.ts and initialize Swagger using the SwaggerModule class.

• Solution

    // src/main.ts
  
    import { NestFactory } from '@nestjs/core';
    import { AppModule } from './app.module';
    import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';
  
    async function bootstrap() {
      const app = await NestFactory.create(AppModule);
  
      const config = new DocumentBuilder()
        .setTitle('Median')
        .setDescription('The Median API description')
        .setVersion('0.1')
        .build();
  
      const document = SwaggerModule.createDocument(app, config);
      SwaggerModule.setup('api', app, document);
  
      await app.listen(3000);
    }
    bootstrap();
  

While the application is running, open your browser and navigate to http://localhost:3000/api. You should see the Swagger UI.