release: v12.0.0 major release (approx. Q3 2026) by kamilmysliwiec · Pull Request #16391 · nestjs/nest

kamilmysliwiec · 2026-02-19T11:07:58Z

PR Checklist

Please check if your PR fulfills the following requirements:

The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
Tests for the changes have been added (for bug fixes / features)
Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

Description

Approximate release window: early Q3 2026

Overview

ESM migration
- All NestJS packages will transition from CommonJS (CJS) to ESM. The packages in this repository (core, common, etc.) have already been migrated. (build: migrate from cjs to esm #16369)
- This should not introduce major breaking changes for existing projects thanks to Node.js require(esm) support.
- The availability of require(esm) was the missing piece that made the move to ESM practical - without it, the migration wouldn't have made much sense. https://joyeecheung.github.io/blog/2024/03/18/require-esm-in-node-js/ https://nodejs.org/api/esm.html#require
CLI (ESM/CJS)
- The NestJS CLI will prompt users to choose whether to generate a CJS or ESM project (ESM projects will use vitest + oxlint by default)
- Webpack -> Rspack ✅ (webpack is now deprecated)
Testing stack changes
- All repositories and sample projects will move from Jest to Vitest (with OXC for TypeScript decorator support). refactor: migrate from mocha, chai, sinon to vitest #16370 sample: migrate all samples to esm and vitest #16371 chore: upgrade to vitest 4 with oxc #16672
- New ESM projects will use Vitest by default.
- The CJS schematic will continue to use Jest.
Linter
- All projects will now use oxlint instead of eslint by default chore: migrate to oxlint from eslint #16674
Website redesign
- A complete redesign of the NestJS websites is coming soon - we're taking them to the next level.
Minor breaking changes
- There will be a few minor breaking changes across other NestJS packages, but nothing significant.
Schema support in route decorators
- All route decorators (e.g., @Body, @Query, etc.) will support a new schema option that accepts a Standard Schema–compatible object. https://standardschema.dev/)
- This enables the use of modern validation libraries such as Zod, Valibot, ArkType, and others, as an alternative to class-validator.
- The same capability will also be available in the serializer interceptor.

PRs:

Packages will soon (possibly in Q2) be released under the next tag to let everyone play with them before they make it to the official latest tag.

Does this PR introduce a breaking change?

Yes
No

Other information

feat: standard schema validation pipe, and standard serializer, introduce internal export subpath

refactor: minor codebase tweaks

sample: migrate all samples to esm and vitest

refactor: migrate from mocha, chai, sinon to vitest

feat(core): add route conflict diagnostics and specificity ordering

julianpoemp · 2026-05-20T08:31:40Z

is it possible to get rid of class-transformer completely with v12? I'm asking because class-transformer didn't receive any updates for the last 4 years. Even if it's so popular, issues und PRs are completely ignored for now.

kamilmysliwiec · 2026-05-20T09:11:51Z

@julianpoemp #16391 (comment)

vkouk · 2026-05-20T19:23:22Z

For those who want to give v12 a shot, all packages have just been released under the next tag on NPM:

@nestjs/common: 12.0.0-alpha.4

@nestjs/core: 12.0.0-alpha.4

@nestjs/microservices: 12.0.0-alpha.4

@nestjs/platform-express: 12.0.0-alpha.4

@nestjs/platform-fastify: 12.0.0-alpha.4

@nestjs/platform-socket.io: 12.0.0-alpha.4

@nestjs/platform-ws: 12.0.0-alpha.4

@nestjs/testing: 12.0.0-alpha.4

@nestjs/websockets: 12.0.0-alpha.4
$ npm i {package_name}@next
if you want to start from scratch, you can also just use npx @nestjs/cli@next new (might need a local @nestjs/schematics@next version installed if you already have a globally installed binary - otherwise it may pick up the old version)

Hey thanks for the early versions. Could we also get config / swagger as well?

kamilmysliwiec · 2026-05-21T07:17:44Z

@vkouk almost there

# Conflicts: # integration/injector/e2e/injector.spec.ts # integration/microservices/e2e/math-grpc.spec.ts # integration/scopes/e2e/request-modules-scope.spec.ts # integration/scopes/e2e/request-scope.spec.ts # lerna.json # package-lock.json # package.json # packages/core/injector/injector.ts # packages/core/test/errors/test/messages.spec.ts # packages/core/test/injector/injector.spec.ts # sample/01-cats-app/package.json # sample/02-gateways/package.json # sample/03-microservices/package.json # sample/04-grpc/package.json # sample/05-sql-typeorm/package.json # sample/06-mongoose/package.json # sample/07-sequelize/package.json # sample/08-webpack/package.json # sample/09-babel-example/package.json # sample/10-fastify/package.json # sample/11-swagger/package.json # sample/12-graphql-schema-first/package.json # sample/13-mongo-typeorm/package.json # sample/14-mongoose-base/package.json # sample/15-mvc/package.json # sample/16-gateways-ws/package.json # sample/17-mvc-fastify/package.json # sample/18-context/package.json # sample/19-auth-jwt/package.json # sample/20-cache/package.json # sample/21-serializer/package.json # sample/22-graphql-prisma/package.json # sample/23-graphql-code-first/package.json # sample/24-serve-static/package.json # sample/25-dynamic-modules/package.json # sample/26-queues/package.json # sample/27-scheduling/package.json # sample/28-sse/package.json # sample/29-file-upload/package.json # sample/30-event-emitter/package.json # sample/31-graphql-federation-code-first/gateway/package.json # sample/31-graphql-federation-code-first/posts-application/package.json # sample/31-graphql-federation-code-first/users-application/package.json # sample/32-graphql-federation-schema-first/gateway/package.json # sample/32-graphql-federation-schema-first/posts-application/package.json # sample/32-graphql-federation-schema-first/users-application/package.json # sample/33-graphql-mercurius/package.json # sample/36-hmr-esm/package.json

AbbasSrour · 2026-05-24T09:10:16Z

Ey love the move to esm, finally.

AbbasSrour · 2026-05-25T10:17:37Z

I noticed that part of using nodenext we are gonna have to have .js extension in source files, is there a way around that?

Trying to resolve it by doing tsc-alias as a post build step.

kamilmysliwiec · 2026-05-25T10:55:36Z

For those who want to give v12 a shot, all packages have just been released under the next tag on NPM:

@nestjs/common: 12.0.0-alpha.4

@nestjs/core: 12.0.0-alpha.4

@nestjs/microservices: 12.0.0-alpha.4

@nestjs/platform-express: 12.0.0-alpha.4

@nestjs/platform-fastify: 12.0.0-alpha.4

@nestjs/platform-socket.io: 12.0.0-alpha.4

@nestjs/platform-ws: 12.0.0-alpha.4

@nestjs/testing: 12.0.0-alpha.4

@nestjs/websockets: 12.0.0-alpha.4
$ npm i {package_name}@next
if you want to start from scratch, you can also just use npx @nestjs/cli@next new (might need a local @nestjs/schematics@next version installed if you already have a globally installed binary - otherwise it may pick up the old version)

12.0.0-alpha.5 has just been published

EDIT @nestjs/swagger@12.0.0-alpha.0 has jusst been published as well

AbbasSrour · 2026-05-25T20:25:14Z

Quick question and excuse my ignorance, is this version gonna support es decorators?

13RTK · 2026-05-26T06:28:13Z

Quick question and excuse my ignorance, is this version gonna support es decorators?

I think nestjs will never support it until include the decorator metadata and parameter decorator in the standard

AbbasSrour · 2026-05-26T07:01:41Z

Quick question and excuse my ignorance, is this version gonna support es decorators?

Quick question and excuse my ignorance, is this version gonna support es decorators?

I think nestjs will never support it until include the decorator metadata and parameter decorator in the standard

makes sense thank you

Roman991 · 2026-05-26T08:01:00Z

nest does not bootstrap with the latest alphas

 Error  The "@nestjs/swagger" plugin is not compatible with Nest CLI. Neither "after()" nor "before()" nor "afterDeclarations()" function have been provided.

    "@nestjs/bullmq": "11.0.4",
    "@nestjs/common": "12.0.0-alpha.5",
    "@nestjs/config": "4.0.4",
    "@nestjs/core": "12.0.0-alpha.5",
    "@nestjs/jwt": "11.0.2",
    "@nestjs/passport": "11.0.5",
    "@nestjs/platform-express": "12.0.0-alpha.5",
    "@nestjs/schedule": "6.1.3",
    "@nestjs/sequelize": "11.0.1",
    "@nestjs/swagger": "12.0.0-alpha.2",
    
     "@nestjs/cli": "12.0.0-alpha.6",
    "@nestjs/schematics": "12.0.0-alpha.9",
    "@nestjs/testing": "12.0.0-alpha.5"

kamilmysliwiec · 2026-05-26T08:07:57Z

@Roman991 could you please create an issue in the swagger repository with a minimum reproduction repo? i couldnt reproduce this bug locally

test(common): add individual spec files for all HTTP exception classes

kamilmysliwiec · 2026-06-01T09:00:32Z

@nestjs/config@12.0.0-next.0 has just been published

kamilmysliwiec · 2026-06-01T09:05:41Z

 - @nestjs/apollo: 13.4.0 => 14.0.0-next.0
 - @nestjs/graphql: 13.4.0 => 14.0.0-next.0
 - @nestjs/mercurius: 13.4.0 => 14.0.0-next.0

have just been published under the next tag

vkouk · 2026-06-05T05:21:08Z

@nestjs/config@12.0.0-next.0 has just been published

Hey! Thanks for the amazing work. Did we also release the bullmq and rest of the packages to next version ?

test(testing): Add unit tests for @nestjs/testing package

glebbash and others added 30 commits March 4, 2025 12:52

fix: make isHttpError check stricter

ccf416d

fix: Handle FastifyError as before

591251a

chore: drop debugging leftover

5be47a0

feat(core): call hooks by components hierarchy level

d1c9ec5

feat(microservices): nats v3 migration

e0a9dfe

chore: revert tsconfig changes

51292e8

feat(common): add generic for argument metadata

ef0984f

feat(common): allow passing errorCode in HttpExceptionOptions

fc405cb

build: migrate from cjs to esm

fa6d45d

refactor: minor tweaks

33f37d6

test: migrate to vitest

6846cd7

test: fix coverage collection, add more tests

288453f

sample: migrate samples to esm

1c046ae

sample: add await to bootstrap calls

62908b4

chore: add root dir to tsconfig

df1537f

refactor: minor codebase tweaks

6586c0d

feat(common): introduce param decorator options

50f0f72

chore: introduce the internal export path

473810c

feat: introduce standard schema serializer

09c8156

fix: dont export plain literal object interface

543142d

chore: address lint errors, and fix ci test errors

fb3ae67

chore: exclude samples that use cli plugins for now

9d4c865

ci: ignore coverage script errors in ci

b6cecd8

sample: fix file upload ts compilation error

d2fd2e6

sample: turn off running sample tests for now

90a40d5

Merge pull request #16373 from nestjs/feat/param-decorator-options

a21fd1d

feat: standard schema validation pipe, and standard serializer, introduce internal export subpath

Merge pull request #16372 from nestjs/refactor/minor-tweaks

b28012e

refactor: minor codebase tweaks

Merge pull request #16371 from nestjs/sample/esm-migration

34f1829

sample: migrate all samples to esm and vitest

Merge pull request #16370 from nestjs/test/vitest-migration

945ca48

refactor: migrate from mocha, chai, sinon to vitest

chore: resolve merge conflicts

70323a1

behrad-kzm and others added 3 commits May 19, 2026 12:00

fix(core): detect conflicts on sorted order when specificity is on

ea5a3cd

fix(core): reset last index before test() on stateful host regexps

78e21ab

Merge pull request #16954 from behrad-kzm/fix/conflicting-routes

6cccd07

feat(core): add route conflict diagnostics and specificity ordering

kamilmysliwiec mentioned this pull request May 19, 2026

test(core,common): register chai-as-promised in async-rejection specs #16973

Closed

kamilmysliwiec added 3 commits May 22, 2026 09:58

test: finalize vitest merge follow-up

a566d45

chore: missing test bootstrap script in package.json

7cea8cb

Merge branch 'master' into v12.0.0

68dfc23

chore: fix merge regression

d91b72c

chore: update lerna and package-lock

cc6f43b

drieshooghe mentioned this pull request May 28, 2026

chore: prep for NestJS 12 (deep-import removal, dual ESM/CJS, Vitest) ocoda/event-sourcing#509

Open

7 tasks

Se3do and others added 2 commits May 28, 2026 10:37

test(common): Add individual spec files for all HTTP exception classes

3a09880

Merge pull request #17041 from Se3do/test/http-exception-classes

1fb92d9

test(common): add individual spec files for all HTTP exception classes

test(testing): Add unit tests for @nestjs/testing package

eb49dd1

Merge pull request #17084 from Se3do/test/testing-module

d1b055e

test(testing): Add unit tests for @nestjs/testing package

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PR Checklist

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julianpoemp commented May 20, 2026

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