unbuild

Free plan

What unbuild is

unbuild is a unified JavaScript build system for producing package builds. Its Rollup-based bundler supports TypeScript and can generate CommonJS and module formats, along with type declarations. It can infer build configuration and entry points from package.json, or use configuration in an unbuild key or a supported JavaScript, TypeScript, or JSON build.config file. For bundleless distributions, its mkdist integration transpiles files individually. The --stub option creates a dist stub with jiti, letting a project be linked during development without watching and rebuilding. unbuild also integrates with untyped for type generation. It checks for potential missing or unused dependencies and can fail CI when it finds build issues; its CLI output shows output size and exports. Listed capabilities include code splitting, tree shaking, source maps, and a plugin API. Published under the unjs GitHub organization, unbuild is free under the MIT license, with no free trial. Its maintainers say they are experimenting with obuild as a next-generation successor based on rolldown.

Who it suits

unbuild suits JavaScript and TypeScript developers building packages who want configuration inference, multiple output formats, and dependency checks. Its stub and bundleless options also suit projects that need those development workflows.

What it does well

Rollup-based bundler supports TypeScript.
Can generate CommonJS, module formats, and type declarations.
Can infer configuration and entries from package.json.
Checks for potentially missing or unused dependencies.
Free under the MIT license.

What to know first

No free trial is listed.
Maintainers are experimenting with obuild as a successor.

Plans

Plan	Billed and limits	Price
unbuild	MIT licensed · JavaScript build system	Free
MIT-licensed open-source software	MIT license · No paid plans stated	Free

As github.com lists them, read 8 Oct 2026. The maker's own page has the final word.

Getting started

Open the unbuild GitHub repository.
Provide configuration through an unbuild key in package.json or a supported build.config file.
Use the Rollup-based bundler for package builds, or mkdist for bundleless distributions.
Use the --stub option to link a project during development without watching and rebuilding.

Verdict

unbuild brings package building, type generation, and dependency checks into one JavaScript build system. Its free MIT-licensed availability may suit projects whose needs match its listed formats and workflows.

Questions

Is unbuild free?

Yes. Its listed plans are free under the MIT license, with no paid plans stated.

Does unbuild offer a free trial?

No. The listed free trial status is no.

Does it support TypeScript?

Yes. Its Rollup-based bundler supports TypeScript and generates type declarations.

How can I configure unbuild?

Configuration can go in an unbuild key in package.json or a build.config file using supported JavaScript, TypeScript, or JSON extensions.

What integrations does it include?

It integrates with mkdist for bundleless file-to-file transpilation and with untyped for type generation.

What is the successor project mentioned by the maintainers?

They say they are experimenting with obuild, a next-generation successor based on rolldown.

Facts from unbuild's own pages

Additional integration: The README lists integration with untyped for type generation. · github.com, 8 Oct 2026
Build checks: It checks for potential missing and unused dependencies and can fail CI when it finds build issues. · github.com, 8 Oct 2026
Bundleless builds: Integration with mkdist enables bundleless distributions with file to file transpilation. · github.com, 8 Oct 2026
Bundling: Its Rollup based bundler supports TypeScript and generates CommonJS and module formats plus type declarations. · github.com, 8 Oct 2026
Configuration: It can infer build configuration and entries from package.json. · github.com, 8 Oct 2026
Configuration formats: Configuration can be provided through an unbuild key in package.json or a build.config file with JavaScript, TypeScript, or JSON extensions listed in the README. · github.com, 8 Oct 2026
Configuration options: Configuration can be provided through an unbuild key in package.json or a build.config file in supported JavaScript, TypeScript, or JSON extensions. · github.com, 8 Oct 2026
Development mode: The --stub option creates a dist stub powered by jiti, so a project can be linked without watching and rebuilding during development. · github.com, 8 Oct 2026
Development workflow: The --stub option creates a dist stub using jiti so a project can be linked without watching and rebuilding during development. · github.com, 8 Oct 2026
License: The repository is released under the MIT license. · github.com, 8 Oct 2026
Maker: The repository is published under the unjs GitHub organization. · github.com, 8 Oct 2026
Output inspection: CLI output includes output size and exports. · github.com, 8 Oct 2026
Purpose: unbuild is a unified JavaScript build system. · github.com, 8 Oct 2026
Successor project: The README says the maintainers are experimenting with obuild as a next generation successor based on rolldown. · github.com, 8 Oct 2026
Type generation: unbuild integrates with untyped for type generation. · github.com, 8 Oct 2026

Where unbuild stands on Freedom251

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