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ReactiveX/rxjs

A reactive programming library for JavaScript
Source code at GitHub https://rxjs.dev
ReactiveX/rxjs.json
{
  "createdAt": "2015-03-15T06:17:10Z",
  "defaultBranch": "master",
  "description": "A reactive programming library for JavaScript",
  "fullName": "ReactiveX/rxjs",
  "homepage": "https://rxjs.dev",
  "language": "TypeScript",
  "name": "rxjs",
  "pushedAt": "2026-08-04T19:52:15Z",
  "stargazersCount": 31697,
  "topics": [
    "javascript",
    "rxjs"
  ],
  "updatedAt": "2026-08-04T18:51:12Z",
  "url": "https://github.com/ReactiveX/rxjs"
}

RxJS

Section titled “RxJS”

CI Release readiness Observable WPT npm stable npm next npm downloads [Apache 2.0]!(LICENSE.txt)

[Observable: platform native]!(docs/rxjs-next/ARCHITECTURE.md#native-selection-and-polyfill-boundary) [Extensions: Symbol keyed]!(docs/rxjs-next/ARCHITECTURE.md#symbol-extension-model)

RxJS is a library for composing asynchronous and event-based programs with Observable values. This repository contains the platform-based next generation of RxJS, planned for release as RxJS 9.

RxJS 9 is prerelease work in development. The planned first beta is 9.0.0-beta.0, but it has not been published to npm yet. The next tag still points to the earlier RxJS 8 prerelease, while RxJS 7 remains the production latest line and continues to be maintained.

Why RxJS 9? What happened to RxJS 8?

Section titled “Why RxJS 9? What happened to RxJS 8?”

RxJS 8 was real work, not a skipped release. Development began years ago and was paused while the Web Platform Observable proposal was finalized. The new implementation is a platform-based generation rather than a continuation of that paused RxJS 8 branch, so it starts at version 9 to make the architectural break unmistakable and avoid presenting the old RxJS 8 work as the released product.

What is different in RxJS 9?

Section titled “What is different in RxJS 9?”
  • RxJS uses the native web-platform Observable when one exists and installs a conforming fallback only when needed.
  • RxJS operators and factories are exact, module-owned Symbols. They do not add string-named RxJS methods to the platform API.
  • Platform Observable behavior and producer-per-subscription behavior are explicit, separate contracts. Use ColdObservable when each direct subscription must create its own producer.
  • Cancellation is built on AbortSignal and the platform Subscriber lifecycle.
  • Published JavaScript is ESM-only. Current Node can bridge require() to the same ESM files; there is no duplicate CommonJS build.

Preview the RxJS 9 API

Section titled “Preview the RxJS 9 API”

The following example shows the planned beta API. Until 9.0.0-beta.0 is published, do not use npm’s next tag to install RxJS 9.

import { ColdObservable } from 'rxjs';
import { map } from 'rxjs/map';


const source = new ColdObservable<number>((subscriber) => {
  subscriber.next(1);
  subscriber.next(2);
  subscriber.complete();
});


source[map]!((value) => value * 2).subscribe(console.log);

Import the Symbol and call it with bracket syntax. A platform method such as observable.map(project) remains the platform contract; observable[map]!(project) is the separately versioned RxJS contract.

Packages and documentation

Section titled “Packages and documentation”
PackagePurposeDocumentation
rxjsSymbol extensions and intentional RxJS primitives[Package guide]!(packages/rxjs/README.md) · [API]!(packages/rxjs/docs/API.md) · [RxJS 7 migration]!(packages/rxjs/MIGRATION.md)
@rxjs/observable-polyfillConditional platform Observable fallback[Package guide]!(packages/observable-polyfill/README.md)
@rxjs/testImplementation-neutral virtual-time and marble testing[Package guide]!(packages/test/README.md)
@rxjs/migrateDeterministic migration engine and canonical agent Skill[Package guide]!(packages/migrate/README.md)

Release support, budgets, and exact environment gates are documented in the [rxjs package]!(packages/rxjs/docs/RELEASE_GATES.md). The irreversible npm publication process is the public [secure release runbook]!(docs/RELEASE_PROCESS.md). The [RxJS 9 security-assurance document]!(packages/rxjs/docs/SECURITY_ASSURANCE.md) explains the release evidence, verification commands, sole-maintainer model, and OpenSSF Scorecard in context. Repository-wide design records live in [docs/rxjs-next]!(docs/rxjs-next/PROJECT_CHARTER.md).

Supported environments

Section titled “Supported environments”

The planned beta supports Node 22.13+ and Node 24 as blocking lanes, with Node 26 in an advisory lane. Current Chrome, Firefox, desktop Safari, Mobile Safari, Deno, Bun, and Webpack 5 are blocking. Every supported consumer receives the same ESM implementation, so Deno and Bun support adds no runtime-specific package or application-bundle code.

Contributing

Section titled “Contributing”

Requires Node 22.13+ and pnpm 10.34.5. Run commands from the repository root.

Terminal window
pnpm install
pnpm --filter rxjs exec vitest --run src
pnpm --filter rxjs run test:package
pnpm run release:check

Start with the [repository contribution guide]!(CONTRIBUTING.md) and the [rxjs package contribution guide]!(packages/rxjs/CONTRIBUTING.md). The active execution queue is [PROJECT_PLAN.md]!(docs/rxjs-next/PROJECT_PLAN.md).

The complete source-pinned RxJS 7 corpus intentionally retains reviewed lifecycle and compatibility divergences, so it is migration evidence rather than a blanket RxJS 9 compatibility gate. Focused source, package, runtime, browser, performance, and WPT commands are the release gates.

Community and governance

Section titled “Community and governance”
  • [Code of Conduct]!(CODE_OF_CONDUCT.md)
  • [Contribution guidelines]!(CONTRIBUTING.md)
  • [Apache 2.0 License]!(LICENSE.txt)
  • Issues
  • Discussions