What is the difference between applying a pipe at the param level vs handler level vs globally in NestJS?

Q: What is the difference between applying a pipe at the param level vs handler level vs globally in NestJS?

// 1. Param level — only transforms 'id' @Get(':id') findOne(@Param('id', ParseIntPipe) id: number, @Query('expand') expand: string) {} // 2. Handler level — ValidationPipe runs on every argument of this method @Post() @UsePipes(new ValidationPipe({ whitelist: true })) create(@Body() dto: CreateUserDto, @Query() query: QueryDto) {} // 3. Controller level — applies to all handlers in the class @UsePipes(ValidationPipe) @Controller('users') export class UsersController {} // 4. Global level — runs for every request in the app // Option A — no DI app.useGlobalPipes(new ValidationPipe()); // Option B — with DI (preferred) providers: [{ provide: APP_PIPE, useClass: ValidationPipe }] Param-level — for transformation pipes like ParseIntPipe, ParseUUIDPipe on specific params. Handler-level — when only some routes need validation with specific options. Controller-level — when all routes in the controller share the same validation rules. Global — for ValidationPipe in most apps; register via APP_PIPE for DI support.

Difficulty: 6/10

Pipes, Scope, Validation

Param-level applies the pipe to a single argument only. Handler-level (@UsePipes on the method) runs the pipe for all arguments of that handler. Controller-level applies to all handlers in the controller. Global applies to every request across the entire app. The global ValidationPipe is the standard for most apps.

Pipe binding at all four levels

Choosing the right binding level:

1
Param-level — for transformation pipes like ParseIntPipe, ParseUUIDPipe on specific params.
2
Handler-level — when only some routes need validation with specific options.
3

What is the difference between applying a pipe at the param level vs handler level vs globally in NestJS?

Scenario Questions

Follow-up Questions