NestJS Swagger (OpenAPI)

npm i @nestjs/swagger

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("Nest API")
    .setDescription("Tech Tutor API documentation")
    .setVersion("1.0")
    .addBearerAuth() // JWT authorization
    .build();

  const document = SwaggerModule.createDocument(app, config);
  SwaggerModule.setup("api", app, document); // /api-এ docs

  await app.listen(3000);
}
bootstrap();

import { ApiProperty } from "@nestjs/swagger";
import { IsEmail, IsString, MinLength } from "class-validator";

export class CreateUserDto {
  @ApiProperty({ example: "রহিম", description: "User নাম" })
  @IsString()
  @MinLength(2)
  name: string;

  @ApiProperty({ example: "rahim@example.com" })
  @IsEmail()
  email: string;

  @ApiProperty({ example: "secret123", minLength: 6 })
  @IsString()
  password: string;
}

import { ApiTags, ApiBearerAuth, ApiResponse } from "@nestjs/swagger";

@ApiTags("users") // section grouping
@Controller("users")
export class UsersController {
  @Get(":id")
  @ApiBearerAuth()
  @ApiResponse({ status: 200, description: "সফল", type: User })
  @ApiResponse({ status: 404, description: "User নেই" })
  findOne(@Param("id") id: string) {
    return this.usersService.findOne(id);
  }
}

# docs URL
http://localhost:3000/api      # swagger UI

# JSON spec
http://localhost:3000/api-json

// production-এ docs বন্ধ রাখা
const app = await NestFactory.create(AppModule);

if (process.env.NODE_ENV !== "production") {
  SwaggerModule.setup("api", app, SwaggerModule.createDocument(
    app,
    new DocumentBuilder().setTitle("API").build(),
  ));
}