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 V4 is currently a release candidate. The main branch contains v4 development.

Install V4 RC

npm install effect@rc

Requirements

• 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-node requires Node.js 22.16 or newer.
• Strict type-checking: the strict flag must be enabled in your tsconfig.json.

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.

Packages

This monorepo contains the core effect package alongside integration packages that extend it. All v4 packages are published under the rc tag on npm.

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-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

Resources

• Documentation (https://effect.website)
• Discord (https://discord.gg/effect-ts)
• Effect v3 source (https://github.com/Effect-TS/effect/tree/v3)
• Effect v4 source (https://github.com/Effect-TS/effect/tree/main)

License

MIT