RxJS development company
We design, build and repair the observable streams behind Angular apps, live dashboards and event-driven Node.js services, choosing each operator deliberately so typeahead search, WebSocket feeds and multi-step forms stay correct, leak-free and testable.
- Senior engineers · IST + EST overlap
- NDA on day 1
- 24-hour reply
- Projects shipped
- 50+
- Code ownership
- 100%
- Client rating
- 4.8/5
- First reply
- 24h
RxJS streams that behave under real event load
As an RxJS development company, Krapton builds and fixes the observable pipelines that drive Angular front ends, real-time dashboards and NestJS services. RxJS rewards precision: the choice between switchMap, concatMap, mergeMap and exhaustMap decides whether a save request is canceled, queued, duplicated or ignored, and a catchError placed on the outer stream can end it after the first failure. Our engineers map each stream before changing it, pin down timing with marble tests in TestScheduler, and replace nested subscriptions with composed operators. We also handle the less visible work: tracing memory leaks to subscriptions that never tear down, tightening share and shareReplay settings, replacing deprecated toPromise calls with firstValueFrom or lastValueFrom, and deciding where Angular signals should take over from BehaviorSubject-based state. RxJS also has no built-in backpressure, so fast producers such as market feeds or sensor streams get throttling, sampling or bounded concurrency chosen for each screen.
RxJS development services
Stream architecture and refactors
We untangle nested subscribe calls and ad hoc Subjects into composed pipelines with clear ownership, choosing the right flattening operator for each user action, request and server push.
Real-time data feeds
WebSocket, Server-Sent Events and polling feeds built with the webSocket subject, retry with backoff, reconnect handling and buffering operators, so live screens stay current without flooding change detection.
Memory leak and race fixes
We find subscriptions that outlive their components, duplicate HTTP calls caused by multiple subscribers, and out-of-order responses, then fix them with takeUntilDestroyed, the async pipe and correct share configuration.
NgRx effects and state
Effects, ComponentStore and SignalStore rxMethod logic written so side effects stay testable, errors are caught inside inner observables, and action streams keep running after a failed request.
RxJS and signals interop
For Angular teams adopting signals, we decide stream by stream what becomes a signal and what stays an observable, then connect the two with toSignal and toObservable without double subscriptions.
NestJS and server streams
Server-side RxJS in NestJS interceptors, microservice clients and Server-Sent Events endpoints, plus explicit conversion between Observables and Promises at each service boundary.
Why teams choose Krapton for RxJS
Senior engineers, fixed scope, and code you own — the things agencies promise and rarely deliver.
Operator choices explained in writing
Every pull request that touches a stream states why it uses switchMap, concatMap, mergeMap or exhaustMap, so your reviewers check intent instead of reverse-engineering it from code.
Timing bugs reproduced, not guessed
Race conditions get a failing marble test first. Virtual time in TestScheduler makes debounce, retry and timeout behavior deterministic, so a fix is proven rather than hoped for.
Lint rules that prevent regressions
We add eslint-plugin-rxjs rules such as no-nested-subscribe and no-unsafe-takeuntil to CI, so the patterns fixed during the engagement do not creep back afterward.
Upgrade steps that stay releasable
RxJS and Angular version moves are split into steps that each pass CI and can ship on their own, so feature work continues during the upgrade.
How a RxJS project runs with Krapton
01
Stream inventory
We list every long-lived subscription, Subject and effect in the affected area, mark which ones leak or race, and agree priorities with your team.
02
Tests before changes
Marble tests capture current behavior, including the bugs, so each refactor shows exactly which emissions changed and which stayed the same.
03
Incremental refactor
Pipelines are rewritten in small pull requests behind existing interfaces, keeping components stable while operators, error handling and teardown improve underneath.
04
Profiling and handover
Heap snapshots in Chrome DevTools confirm leaks are gone, and each key stream ships with a marble diagram and notes your developers can maintain.
The RxJS stack we build with
RxJS development: questions answered
What does an RxJS development company actually work on?
Mostly the parts of an application where events arrive over time: search-as-you-type, live prices or telemetry, forms with dependent requests, polling, retries and WebSocket reconnects. An RxJS development company like Krapton designs those pipelines, fixes leaks and races in existing ones, writes marble tests, and helps Angular teams split state between observables and signals. Plain request-response features rarely need specialist RxJS work.
When is RxJS the wrong tool?
When the data is a single value or a one-off request. Promises and async/await express that more clearly, and React projects usually get more from TanStack Query or a small store than from hand-written streams. RxJS pays off when you must combine, cancel, throttle or retry several event sources; using it everywhere adds a learning curve and debugging cost that simple features do not need.
How do you fix RxJS memory leaks in an Angular app?
By finding subscriptions that never complete and giving each one an owner. We take heap snapshots, look for destroyed components still referenced by subscribers, then use the async pipe, takeUntilDestroyed or toSignal so teardown follows the component lifecycle. We also check shareReplay calls, because a shared replay without refCount can keep its source subscribed after every consumer is gone.
Can you migrate our codebase from RxJS 6 to RxJS 7?
Yes, and it is usually a contained job. RxJS 7 deprecates toPromise, multi-argument subscribe calls and several operator signatures, and from 7.2 operators can be imported directly from the main rxjs package. We upgrade alongside your Angular version, fix the type errors that stricter RxJS 7 typings expose, and wrap the riskiest streams in marble tests so behavior does not drift.
How is the cost of RxJS work decided?
It is scoped from the reactive code itself. The drivers are how many streams and effects are involved, how tangled the existing subscriptions are, whether tests exist, the Angular and RxJS versions in use, and whether the work includes signals adoption or NgRx changes. A short review of the code gives enough detail to scope it accurately.
Ready to build? Tell us what you have in mind.
Send a short brief and a senior engineer will reply within one business day with next steps — no sales fluff.