effect

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# Effect

Effect is a library for building robust, maintainable, type-safe, and production grade applications in TypeScript. It helps you handle the hard problems at scale: typed errors, dependency injection, structured concurrency, scheduling, tracing, and unified schema validation.

> **Effect 4.x is a long-term support (LTS) release.** If you are upgrading from Effect 3.x, follow the [migration guide](MIGRATION.md).

## Installation

```sh
npm install effect
```

## Requirements

- **TypeScript 5.9 or newer.** TypeScript 7 is recommended for the best performance and compatibility with [Effect's TypeScript tooling](https://github.com/Effect-TS/tsgo#installation).
- **Node.js 22.19 or newer** is the general minimum for running Effect on Node.js.
- **Strict type-checking:** the `strict` flag must be enabled in your `tsconfig.json`.

## Links

- [Website](https://effect.website): documentation, guides, and news
- [Discord](https://discord.gg/effect-ts): ask questions, share what you're building, and talk to the core team
- [Community](https://effect.website/community-hub): meetups and events, or bring Effect to your own
- [Issues](https://github.com/Effect-TS/effect/issues): bug reports and feature requests
- [Jobs](https://effect.website/effect-jobs): companies hiring Effect developers
- Follow us on [X](https://x.com/EffectTS_), [Bluesky](https://bsky.app/profile/effect-ts.bsky.social), and [LinkedIn](https://www.linkedin.com/company/effect-ts)

## Let's talk

Whether your team is considering Effect, rolling it out, or already running it in production, we'd love to hear from you: what you're building, what works, and what you need from Effect next.

- **Talk to the maintainers.** Introduce your team on [Discord](https://discord.gg/effect-ts) or email [contact@effectful.co](mailto:contact@effectful.co). We're happy to connect privately on Slack or Discord for feedback and help with adoption.
- **Production support.** We're exploring how to better support teams running Effect in production. If your organization has specific support needs, let's discuss them.
- **Adoption help.** Our [adoption partners](https://effect.website/adoption-partners) offer implementation, consulting, team extension, training, and commercial support.

Feedback from teams using and evaluating Effect directly shapes what we stabilize and build next.

## Long-term support

Teams depend on Effect for systems they expect to run for years. Effect 4.x is a long-term support (LTS) release with the following guarantees:

- At least three years of support, including bug and security fixes.
- Bug fixes for one year after the next major version is released.
- Security fixes for two years after the next major version is released.

Stable API