NestJS v12.0.0

NestJS v12.0.0

NestJS 12 is centered around ESM-ready packages, first-class Standard Schema support for validation and serialization, a rebuilt CLI, and native observability through the new @nestjs/observe SDK.

Existing CommonJS applications keep working — migrating your own code to ESM is entirely optional.

📖 Full migration guide

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Upgrading

Upgrade the CLI first, since the upgrade command ships with it:

npm i -g @nestjs/cli@latest

Then, from the root of your project:

nest upgrade

nest upgrade moves every @nestjs/* package to its v12-compatible major at once and applies the mechanical parts of the migration for you — nest-cli.json webpack options, the GraphQL playground → graphiql rename and subscriptions transport swap, the NATS package replacement, @nestjs/config validation options, Jest and Joi bumps — then prints a report of everything it changed and everything you still need to review by hand. Run it with --dry-run first to see that report without touching your files.

It deliberately does not migrate your project to ESM, Vitest, or oxlint. Those are the defaults for newly generated projects; existing projects adopt them on their own schedule.

Node.js: v12 requires Node.js v20.19+ or v22.12+. Both require(esm) and the ESM packages depend on it; the upgrade command refuses to run on older releases (including the 21.x line). The latest active LTS is recommended.

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Highlights

ESM packages

All core Nest packages now ship as ESM. Thanks to require(esm) in modern Node.js, most existing CommonJS applications continue to work without a rewrite. Review custom bootstrapping scripts, build tooling, and test runners if they assume CommonJS-only packages.

nest new now asks whether to scaffold a CommonJS or an ESM project.

Standard Schema validation

Route parameter decorators — @Body(), @Query(), @Param(), @RawBody() — accept a new schema option, designed for Standard Schema compatible libraries such as Zod, Valibot, and ArkType:

@Post()
create(@Body({ schema: createUserSchema }) body: CreateUserDto) {
  return this.usersService.create(body);
}

@Get(':id')
findOne(@Param('id', { schema: z.coerce.number().int().positive() }) id: number) {
  return this.usersService.findOne(id);
}

The decorator only attaches metadata; register the new StandardSchemaValidationPipe to validate against it:

app.useGlobalPipes(new StandardSchemaValidationPipe());

The same schemas feed OpenAPI generation. The decorator-based class-validator workflow remains fully supported, with no plan to remove it.

Standard Schema serialization

StandardSchemaSerializerInterceptor validates and transforms outgoing responses with the same ecosystem:

@UseInterceptors(StandardSchemaSerializerInterceptor)
@SerializeOptions({ schema: userResponseSchema })
@Get(':id')
findOne(@Param('id') id: string) {
  return this.usersService.findOne(id);
}

Pick per use case: ValidationPipe / ClassSerializerInterceptor for class-based DTOs, the Standard Schema variants when your schemas already exist.

Native observability — @nestjs/observe

The official NestJS Observe SDK plugs into Nest's own request lifecycle through the instrument application option, rather than patching the HTTP server like a generic APM agent. Requests, jobs, errors, and traces are reported in terms of your controllers, providers, resolvers, and queue consumers:

export const { ObserveModule, ObserveInstrument } = createObserveModule();

const app = await NestFactory.create(AppModule, {
  instrument: ObserveInstrument,
});

Auto-instrumentation covers HTTP, GraphQL, gRPC, and microservice transports, plus queue consumers and cron runs — no manual span wiring and no collector to run. Opt-in and new; nothing to migrate. nest new and nest upgrade can wire it up for you (--observe). See the Observability chapter.

Config module on Standard Schema

@nestjs/config moves from Joi-specific validation to Standard Schema. validationSchema now accepts any compatible schema:

ConfigModule.forRoot({
  validationSchema: z.object({
    NODE_ENV: z.enum(['development', 'production', 'test']).default('development'),
    PORT: z.coerce.number().default(3000),
  }),
});

Existing Joi schemas still work with two caveats: upgrade to Joi v18+ (the first release implementing Standard Schema), and move library-specific settings under validationOptions.libraryOptions.

Route conflict diagnostics

Routes are registered in declaration order, so on order-sensitive adapters @Get(':id') can silently shadow a @Get('me') declared after it. Two opt-in options surface this:

const app = await NestFactory.create(AppModule, {
  routeConflictPolicy: { duplicate: 'error', shadow: 'warn' },
  routeResolutionStrategy: 'specificity',
});

Both default to the previous behavior, so nothing changes unless you set them.

Machine-readable error codes

HttpExceptionOptions accepts an errorCode that is serialized into the response body, so clients branch on a stable identifier instead of parsing message strings:

throw new BadRequestException('Password is too weak', { errorCode: 'WEAK_PASSWORD' });

Structured logging params

ConsoleLogger now treats plain objects passed after the message as structured params of the same log entry instead of separate records:

logger.log('User created', { userId: 1, email: 'foo@bar.com' });

In JSON mode they nest under params, or spread into the root with flattenParams. On by default; set structuredParams: false to restore the old behavior.

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CLI (@nestjs/cli v12)

The CLI was rebuilt in nestjs/nest-cli#3280: the entire source migrated to ESM, tests moved from Jest to Vitest, e2e tests were added for every command, and command classes were refactored to take typed context objects instead of untyped inputs and option arrays.

New commands

• nest upgrade (alias update) — upgrades a v11 project to v12 and applies the migration steps described above.
• nest deploy — deploys your application to the cloud via Mau, installing @nestjs/mau on first use and forwarding every argument straight through.

Defaults and tooling

• Rspack is the new default bundler for monorepos. The --webpack / --webpackPath flags (and their webpack / webpackConfigPath counterparts in nest-cli.json) are deprecated in favor of --builder rspack.
• oxlint replaces ESLint in generated projects.
• Vitest is the default test runner for ESM projects; CommonJS projects continue with Jest.
• bun is now a supported package manager, alongside npm, yarn, and pnpm.
• The decorator schematic generates decorators using the preferred Reflector.createDecorator() form. The angular schematic has been removed.

New options

• nest build / nest start: --rspackPath [path], --emit-declarations (SWC), --no-type-check, --silent
• nest build: --parallel [concurrency], for building monorepo projects in parallel with --all
• nest-cli.json: includeLibraryAssets, for copying library assets into an application build

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Breaking changes

Change	What to do
Packages ship as ESM	Usually nothing — require(esm) keeps CommonJS apps working. Review custom bootstrapping, bundler, and test-runner config.
Node.js v20.19+ / v22.12+ required	Upgrade Node; the 21.x line is not supported.
Lifecycle hooks are now invoked by component hierarchy level	Review ordering assumptions between related providers/modules in init, teardown, and tests.
NATS v3 — the nats package is replaced by @nats-io/transport-node	npm uninstall nats && npm install @nats-io/transport-node; update direct imports. Packets are now serialized as JSON strings and custom deserializers receive the full NATS message — read payloads with msg.json().
GraphQL subscriptions — subscriptions-transport-ws support removed	Switch to graphql-ws; the protocols are wire-incompatible, so clients must be updated. Review onConnect callbacks.
GraphiQL is the default GraphQL IDE	Replace playground with graphiql; pass an options object to customize.
@nestjs/config validates through Standard Schema	Keep Joi by upgrading to v18+ and moving library settings under validationOptions.libraryOptions.
Pipe transform signatures refined; ArgumentMetadata is now generic	Adjust hand-written custom pipe signatures if the compiler complains.
ConsoleLogger structured params on by default	Set structuredParams: false to restore the previous output.
Webpack CLI workflows deprecated	Migrate to --builder rspack.
angular schematic removed	—

Most of these are handled automatically by nest upgrade.

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Also in this release

• ValidationPipe error format — a new option controls the shape of validation error responses.
• gRPC exception filter — GrpcExceptionFilter and status-specific exceptions map errors to proper gRPC status codes instead of UNKNOWN.
• Regex Kafka patterns — @MessagePattern() and @EventPattern() accept a RegExp on the Kafka transport.
• Request-scoped WebSocket gateways — gateways support request-scoped providers, with the socket injectable via the REQUEST token.
• WebSocket disconnect reason — handleDisconnect can receive the reason for the disconnection.
• Microservices pre-request hook — a new hook runs before a message handler is invoked.
• Express graceful shutdown — the Express adapter drains in-flight requests on shutdown.
• HTTP adapter error mapping — reworked across core, Express, and Fastify adapters.

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Thanks

Thank you to everyone who contributed code, issues, reproductions, and reviews to this release. 💛

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