NestJS 12.0.0

Kamil Mysliwiec and the NestJS core team have shipped version 12.0.0 of the progressive Node.js framework, a major release released on August 27, 2026. The update is centered on ESM-ready packages, first-class Standard Schema support for validation and serialization, a rebuilt command-line interface, and native observability through the new @nestjs/observe SDK.

What Changed

Version 12 reorganizes the framework around modern JavaScript packaging while keeping existing CommonJS applications working. Existing projects upgrade through the rebuilt CLI using the nest upgrade command, which moves every @nestjs package to its v12-compatible major and applies the mechanical parts of the migration automatically. Migrating your own application code to ESM remains entirely optional.

Several headline changes stand out:

• ESM packages — the nest new scaffold now asks whether to create a CommonJS or an ESM project.
• Standard Schema validation — a new StandardSchemaValidationPipe validates against standard schemas, with the same schemas feeding OpenAPI generation. The class-validator workflow remains fully supported.
• Standard Schema serialization — a StandardSchemaSerializerInterceptor brings the same schema-driven approach to response serialization.
• Native observability — the @nestjs/observe SDK plugs into Nest request lifecycle through the instrument application option instead of patching the HTTP server, so traces report in terms of controllers, providers, resolvers, and queue consumers.
• Config on Standard Schema — @nestjs/config moves from Joi-specific validation to Standard Schema, while existing Joi schemas keep working with Joi v18+.

New Command Line

The CLI was rebuilt with its source migrated to ESM and its tests moved from Jest to Vitest. Rspack becomes the default bundler for monorepos, oxlint replaces ESLint in generated projects, Vitest is the default test runner for ESM projects, and bun is now a supported package manager alongside npm, yarn, and pnpm. The nest deploy command deploys applications to the cloud through Mau, and the angular schematic has been removed.

Breaking Changes

Two areas require attention when upgrading. Lifecycle hooks are now invoked by component hierarchy level, so developers should review ordering assumptions between related providers and modules in init, teardown, and tests. In addition, @nestjs/config now validates through Standard Schema, which means keeping Joi requires upgrading to Joi v18+ and moving library-specific settings under validationOptions.libraryOptions. Most migration steps are handled automatically by the nest upgrade command.

Why It Matters

Version 12 marks a meaningful shift toward schema-driven contracts and lower-friction observability for a framework used to build large enterprise server applications. Node.js 20.19+ or 22.12+ is required, with the latest active LTS recommended.

What Next

Teams planning to upgrade should run the CLI update first, then nest upgrade from the project root, verify their test suites, and review the migration guide for anything the automated tool cannot handle. The new defaults target newly generated projects, so existing applications can adopt ESM, Vitest, and oxlint on their own schedule.