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.
Installation
npm install effectRequirements
- TypeScript 5.9 or newer. TypeScript 7 is recommended for the best performance and compatibility with Effect's TypeScript tooling.
- Node.js 18 or newer is the general minimum for running Effect on Node.js. Some integration packages require newer runtimes; for example,
@effect/sql-sqlite-noderequires Node.js 22.16 or newer. - Strict type-checking: the
strictflag must be enabled in yourtsconfig.json.
Links
- Website: documentation, guides, and news
- Discord: ask questions, share what you're building, and talk to the core team
- Community: meetups and events, or bring Effect to your own
- Issues: bug reports and feature requests
- Jobs: companies hiring Effect developers
- Follow us on X, Bluesky, and LinkedIn
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 or email 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 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 APIs reserve breaking changes for major releases. APIs marked unstable may change in minor releases, and experimental APIs may change in patch releases.
Effect v3
The Effect v3 source code is available on the v3 branch, which is also where issues and pull requests meant for Effect v3 should be targeted. To upgrade, see the migration guide.
Packages
This monorepo contains the core effect package alongside integration packages that extend it. All packages listed below are released together with synchronized versions.
| Package | Description | API Reference |
|---|---|---|
effect |
The core package | docs |
@effect/platform-browser |
Platform services for the browser | docs |
@effect/platform-bun |
Platform services for Bun | docs |
@effect/platform-deno |
Platform services for Deno | docs |
@effect/platform-node |
Platform services for Node.js | docs |
@effect/platform-node-shared |
Shared services for Node.js-compatible runtimes | docs |
@effect/sql-clickhouse |
SQL client for ClickHouse | docs |
@effect/sql-d1 |
SQL client for Cloudflare D1 | docs |
@effect/sql-libsql |
SQL client for libSQL | docs |
@effect/sql-mssql |
SQL client for Microsoft SQL Server | docs |
@effect/sql-mysql2 |
SQL client for MySQL | docs |
@effect/sql-pg |
SQL client for PostgreSQL | docs |
@effect/sql-pglite |
SQL client for PGlite | docs |
@effect/sql-sqlite-bun |
SQL client for SQLite via bun:sqlite |
docs |
@effect/sql-sqlite-do |
SQL client for Cloudflare Durable Objects SQLite | docs |
@effect/sql-sqlite-node |
SQL client for SQLite via node:sqlite |
docs |
@effect/sql-sqlite-react-native |
SQL client for SQLite in React Native | docs |
@effect/sql-sqlite-wasm |
SQL client for SQLite compiled to WebAssembly | docs |
@effect/ai-anthropic |
Anthropic provider for the Effect AI modules | docs |
@effect/ai-openai |
OpenAI provider for the Effect AI modules | docs |
@effect/ai-typesafe |
TypeSafe decision provider for the Effect AI modules | docs |
@effect/ai-openai-compat |
OpenAI-compatible API provider for the Effect AI modules | docs |
@effect/ai-openrouter |
OpenRouter provider for the Effect AI modules | docs |
@effect/atom-react |
React bindings for Effect Atom | docs |
@effect/atom-solid |
SolidJS bindings for Effect Atom | docs |
@effect/atom-vue |
Vue bindings for Effect Atom | docs |
@effect/opentelemetry |
OpenTelemetry integration | docs |
@effect/vitest |
Helpers for testing with Vitest | docs |
@effect/docgen |
Documentation generator for Effect projects | docs |
@effect/doctest |
Runs JSDoc examples as Vitest tests | docs |
@effect/openapi-generator |
Generate Effect code from OpenAPI specifications | docs |
License
MIT
