What are the best alternatives to RxJS for reactive programming in JavaScript?

RxJS still beats every alternative for complex async stream composition, but most apps only need a fraction of its 100-plus operators. Version 7 trimmed the full bundle to about 19KB minified and gzipped, half of version 6's 52KB, yet lighter tools like xstream stay under 30KB with just 26 core operators.

When does RxJS still make sense?

RxJS earns its size when an app needs to combine, cancel, retry, and time multiple async sources at once, like autocomplete search paired with debouncing, request cancellation, and websocket merging. Angular's HttpClient and Router still return Observables, so RxJS stays present in most Angular codebases even as Signals take over local component state. Teams already fluent in its operators, such as map, switchMap, and combineLatest, rarely benefit from switching, since the migration cost usually outweighs the bundle savings.

When should you reach for something lighter?

If the app mostly needs to track a handful of values and re-render when they change, a signals-based approach removes the ceremony of subscribing, piping, and unsubscribing. React or Vue apps that only used RxJS for simple state, not stream composition, can typically replace it with built-in state hooks or a small library. xstream and Bacon.js fit projects that want stream semantics without loading RxJS's full operator catalog, and native async iterators handle straightforward async sequences without adding a dependency at all.

Who fits what?

Angular teams building on HttpClient and the Router still need RxJS regardless of preference, though new component state can move to Signals. Framework-agnostic apps doing heavy stream composition, with multiple event sources, backpressure, and retries, still benefit most from RxJS's maturity. Everyone else managing simpler async state has real, smaller options now, and picking one usually comes down to whether the team wants stream operators at all or just reactive values.

Published at: July 21, 2026