nestjs/nest · error · BadRequestException

Validation failed

Error message

Validation failed

What it means

Error "Validation failed" thrown in nestjs/nest.

Source

Thrown at sample/10-fastify/src/common/pipes/parse-int.pipe.ts:9

import { BadRequestException } from '@nestjs/common';
import { PipeTransform, Injectable, ArgumentMetadata } from '@nestjs/common';

@Injectable()
export class ParseIntPipe implements PipeTransform<string> {
  async transform(value: string, metadata: ArgumentMetadata) {
    const val = parseInt(value, 10);
    if (isNaN(val)) {
      throw new BadRequestException('Validation failed');
    }
    return val;
  }
}

View on GitHub (pinned to 6ec0e2783d)

Solutions

1. Send a numeric value for the :id route parameter; the parse-int pipe rejects non-numeric input.
2. Fix the client request URL to include an integer id.
3. If arbitrary string ids are allowed, drop the ParseIntPipe from the parameter.

Example fix

// client: GET /cats/42
@Get(':id')
findOne(@Param('id', ParseIntPipe) id: number) {}

When it happens

Trigger: Thrown at sample/10-fastify/src/common/pipes/parse-int.pipe.ts:9 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nestjs/nest@6ec0e2783d (2026-08-03). Data as JSON: /data/errors/c4b2403bcdea6ed2.json. Report an issue: GitHub.