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Node.js DevelopmentAPIS & REALTIME

We Build APIs and Realtime Backends in Node.js

  • WebSocket services
  • Microservices
  • Gateway and BFF layers
  • Queue workers

Node is at its best when a request spends most of its life waiting — on a database, a queue, another service, or a socket held open. That is what we use it for, and we build around the event loop's one hard rule: never block it CPU-heavy work goes to a worker thread, a queue, or a different runtime altogether.

  • Express, NestJS, Fastify
  • TypeScript end to end
  • Load-tested before launch
Active LTS line
v20 LTS
Across the stack
TypeScript
node-api — production0 errors · PM2 cluster

Access Logs

  • 09:41:02GET/api/v1/users20024ms
  • 09:41:03POST/api/v1/auth/login20118ms
  • 09:41:05PUT/api/v1/orders/782920042ms
  • 09:41:07POST/api/v1/webhooks2028ms
  • 09:41:09GET/api/v1/ws/connect1013ms

Live Metrics

Requests / sec
218
Heap memory used
52.4%
Event loop lag
0.8ms
Active handles
42

Node.js v20.11 LTS · V8 11.3

Node.js v20 LTS · Express 4.x

  • Express.js
  • NestJS
  • MongoDB
Runtime
v20 LTS · ESM and native test runner

Where Node.js Earns Its Place

One Thread, One Rule, and Why Node.js Suits Some Work

  • Express.js
  • NestJS
  • MongoDB
  • Redis
  • Socket.io
  • GraphQL

Node runs your JavaScript on one thread and hands the waiting to the operating system. For a service whose work is mostly I/O — reading a database, calling another API, pushing messages down a socket — that model holds a lot of concurrent connections on modest hardware, because idle connections cost almost nothing.

The second benefit is organisational. One language across the browser, the server and the build means shared types, shared validation, and no translation layer between a frontend and backend developer. With TypeScript on both sides, a change to an API contract fails at compile time rather than in a staging bug report.

The trade-offs are just as concrete. That single thread is unforgiving: one synchronous loop over a large array stalls every request in flight, so CPU-bound work belongs in a worker thread, a queue or another service. npm's reach is its own risk — every dependency is code you now own, so we keep the tree small, pinned and audited. And an unhandled rejection in an async path still takes a process down if nobody catches it, which is why error handling and structured logging go in first, not last.

  • Express, NestJS or Fastify
  • WebSockets that survive a reconnect
  • Services split when there's a reason
  • PostgreSQL and MongoDB
  • REST and GraphQL, typed
  • A small, audited dependency tree
Node.js v20 LTSJavaScript runtime on V8
Support & upgrades
Ongoing
V8 · ESM · worker threads
Node.js v20 LTS
Idle connections cost little
Non-blocking I/O

Node.js Development Services

What We Build With Node.js

Web Applications on Node

Web applications where the backend's job is coordination: pulling from several sources, streaming the response, and keeping the page in step. Request handlers stay thin and anything slow goes to a queue, so a spike on one endpoint does not drag the rest of the app down with it.

  • Streamed responses
  • Slow work moved off the request
  • Types shared with the frontend
  • Express.js
  • NestJS
  • Socket.io

Bespoke Node Services

Applications built around your domain rather than a template. NestJS when a larger team benefits from imposed structure and dependency injection; Express or Fastify when the service is small enough that structure would only be ceremony. That call gets made on the shape of your team, not on preference.

  • Framework chosen per service
  • Typed domain models
  • You own the source
  • Node.js v20
  • TypeScript
  • Docker

APIs and Service Integration

REST or GraphQL with the contract written down first, so client and server can be built in parallel. Outbound calls get timeouts, retries with backoff and a circuit breaker — because the failure that hurts is rarely a dependency that is down, it is one that is slow.

  • Schema-first contracts
  • Timeouts, retries, circuit breakers
  • OAuth2 and JWT with rotation
  • Express
  • GraphQL
  • Swagger

Real-Time and Streaming Features

Chat, presence, live dashboards, collaborative editing. The sockets are the easy part. The work is in reconnection, replaying what a client missed while it was away, and fanning messages out across more than one server instance — which is where Redis pub/sub or a broker comes in.

  • Reconnect and replay
  • Fan-out across instances
  • Presence and room state
  • Socket.io
  • WebSockets
  • Redis Pub/Sub

Moving Existing Systems to Node

Moving off a legacy backend works best in slices. New routes are served by Node behind the same public URL while the old system keeps handling the rest, so every slice can be measured and reversed. A rewrite that lands all at once has no rollback worth the name.

  • Strangler-fig routing
  • Slice-by-slice cutover
  • Old and new running in parallel
  • Migration
  • Microservices
  • CI/CD

Runtime Support and Maintenance

Dependency updates, LTS upgrades, security advisories, and the slow memory leak that only shows itself after a week of uptime. We watch event-loop lag and heap growth in particular, because between them they explain most Node incidents. Cover and response times are agreed per engagement.

  • Event-loop lag and heap tracking
  • Dependency audits and updates
  • Node LTS upgrades
  • Monitoring
  • Upgrades
  • PM2

Node Architecture Consulting

An outside read on the architecture: whether your services should be separate services at all, where the event loop is being blocked, what the dependency tree exposes you to, and whether Node is the right runtime for the part of the workload that is actually hurting. Sometimes the answer is that it is not.

  • Profiling and event-loop review
  • Service boundary assessment
  • Dependency risk audit
  • Architecture
  • Profiling
  • NestJS

Not sure Node is the right runtime for the job?

Tell us what the service has to do, and we will say where Node fits and where it does not.

Talk to a Node Developer

Framework Choices

The Node.js Frameworks We Reach For

There is no best framework here, only the one that fits the size of the team and the shape of the service. This is how we choose.

Most Used

Express.js

Minimal, and that is the point

Thin routing and middleware over Node's HTTP server, with the ecosystem supplying everything else. It imposes no structure — which suits a small service and hurts a large team unless you bring conventions of your own. Still the safest default when a service is genuinely small.

  • Middleware composition
  • Nothing you did not add
  • Enormous ecosystem
Structured

NestJS

Structure imposed on purpose

TypeScript-first, with modules, dependency injection and decorators in an Angular-like arrangement. The structure costs boilerplate and a learning curve; it buys a codebase where six developers write things the same way. Worth it above a certain team size, overkill below it.

  • TypeScript throughout
  • Dependency injection
  • OpenAPI generation
Minimal

Koa.js

Express, without the callbacks

From the same authors as Express: async middleware in a cascade, with one context object, so errors travel through try/catch instead of a callback convention. The ecosystem is much smaller, so expect to write more of the plumbing yourself.

  • Async middleware cascade
  • Clean error propagation
  • Small surface area
Full-Stack

Meteor.js

Full stack with data sync built in

A full-stack JavaScript platform where client and server share a data protocol and updates propagate on their own. Quick for the kind of app it was designed around. It is a strong opinion to adopt, and not a cheap one to back out of later.

  • Reactive data sync
  • Shared client-server code
  • DDP protocol
Real-Time

Socket.io

WebSockets with the awkward parts handled

A library rather than a framework. It covers reconnection, acknowledgements, rooms and transport fallback, and with a Redis adapter it broadcasts across instances. Raw WebSockets are lighter, but you generally end up rebuilding most of this by hand.

  • Reconnect and acknowledgements
  • Rooms and namespaces
  • Multi-instance adapter
API-First

Hapi.js

Configuration over convention

Routes declared as configuration, with validation, caching and authentication as first-class parts of the framework rather than middleware you assemble. Fewer developers know it, which is a genuine hiring consideration, but it suits API-heavy work well.

  • Validation on every route
  • Plugin system
  • Config-driven routing

Why Node.js

What Node.js Is Genuinely Good At

Concurrency Without Threads

One thread plus non-blocking I/O means thousands of open connections cost memory rather than CPU. For a service that mostly waits on other systems, that is a very different scaling curve from thread-per-request.

Streaming as a First Principle

Streams are part of the runtime, so large uploads, exports and proxied responses move through the process in chunks instead of being buffered whole. That is the difference between flat memory and an out-of-memory restart.

One Language Across the Stack

The same types, validators and helpers on both sides of the wire. Fewer handoffs between frontend and backend, and a contract change that breaks the build rather than someone's screen.

Realtime Without Extra Machinery

WebSockets, server-sent events and pub/sub sit naturally on an event loop. Chat, presence and live dashboards are ordinary work here rather than a subsystem bolted on the side.

The Largest Package Registry

Almost every integration you need already has a client. That is real leverage and a real liability — each dependency is code you now maintain, so we keep the tree small enough to actually audit.

Cheap to Run and to Staff

A small memory footprint per instance, quick starts in serverless, and a hiring pool the size of JavaScript's. The scarce skill is not writing Node; it is knowing what must never run on the event loop.

Why Choose Aryavos

How We Work On Node.js Projects

  • TypeScript From the Start

    Strict mode on, types shared between client and server, and runtime validation at the edges — because a type tells you nothing about what a third party actually sent you.

  • Async Errors Handled Deliberately

    Every promise has an owner. Unhandled rejections fail the build rather than the process, retries are idempotent, and errors carry enough context to be findable in a log a week later.

  • Services Split Only With a Reason

    Separate services where teams or scaling profiles genuinely differ, one deployable where they do not. A distributed system you did not need is the most expensive thing anyone can hand you.

  • Engagement Models That Fit

    Fixed scope, time and materials, or a developer working inside your team. We will say which one suits the work, including when that is the cheaper option for you.

  • Numbers Before Launch

    The service goes under realistic traffic before release, with p99 latency, event-loop lag and memory watched under sustained load, so the first surprise is not a real one.

  • Every Change Reviewed

    A second developer reads each pull request, and CI runs lint, type checks, tests and a dependency audit before anything can merge.

  • Security in the Defaults

    Security headers, rate limiting, validation on every route, secrets from the environment rather than the repository, and advisories that fail the build. Designed to support the controls you have to evidence, with scope agreed per engagement.

  • Support After Launch

    Monitoring you can see for yourself, response times written into the agreement rather than implied, and a regular cadence for Node LTS and dependency updates.

Have a Node service to build, or one that needs fixing?

APIs and realtime · Migrations · Performance work

Talk to a Node Developer
Technology Stack

The Node Stack Behind Your Build

Language and Runtime

NodeTypescriptJavascriptServerlessExpress

Front-End

BootstrapReactAngularjQueryVue

Architecture

MVCMVPMicroservicesMVVM

Frameworks and Libraries

TypescriptJavascriptExpressServerless

Database

MySQLMongoDBOracleFirebaseMS-SQLMariaDBPostgreSQLElasticsearch

Deployment

AzureAWSDockerGoogle CloudKubernetes

Testing

SeleniumKatalonTest RailOWASP ZAPPostman

ORMs

TypeORMSequelizeGraphQL

Caching

MemcachedRedis

Project Management

AsanaSlackTrelloJiraMicrosoft Teams

Development Process

From Brief to a Running Service

Six stages. The runtime and service boundaries are decided in the first one, because those are the choices you live with.

We map the workload before choosing anything: which requests wait on I/O, which are compute-heavy, what has to be immediate and what can be queued. That answers the framework question, the database question, and the one that matters most — which parts of this should not run in Node at all.

Key Deliverables

  • Workload Map
  • Picking the Framework
  • Data & Queue Design
  • Project Roadmap

Industries We Serve

Where Node Fits Best

Node fits where a backend spends its time coordinating rather than computing. What that looks like, sector by sector.

  • Commerce and Marketplaces

    Storefront APIs, inventory several systems write to, and checkout traffic that arrives in bursts. Node handles the coordination well; the discipline is keeping the payment path idempotent so a retry never charges twice.

  • Gaming

    Matchmaking, lobbies, leaderboards and session state over WebSockets. Node suits the messaging layer. It does not suit physics or simulation, which belong in a process built for compute.

  • Education

    Live classrooms, quiz engines and progress tracking, with load that arrives all at once when a session starts. Video processing and report generation go to workers, so a lecture never competes with a PDF export.

  • Healthcare

    Patient portals, appointment flows and device or monitoring feeds. Access control enforced in the service rather than the client, and designed to support the privacy obligations you operate under, with scope agreed per engagement.

  • Food & Restaurant

    Order intake, kitchen displays and courier tracking, where a few seconds of staleness is visible to a customer. Socket updates for the live view, a queue for everything that can afford to be a moment late.

  • Logistics

    Fleet telemetry and shipment events arriving continuously from many devices. Ingest is buffered and streamed rather than handled request by request, because dropping position updates in a spike is worse than a slightly older map.

  • Banking & FinTech

    Payment APIs, transaction feeds and reconciliation. Handlers are idempotent, every outbound call is bounded by a timeout, and the audit record is written before the response goes back. Designed to support the controls you have to evidence.

  • HRMS

    Employee records, attendance, approvals and payroll. The interactive parts stay in Node; a payroll run is batch compute and belongs in a scheduled worker rather than on the request path.

  • Travel

    Search and booking against supplier APIs that are slow and occasionally wrong. Fan-out with per-supplier timeouts, cached results with a stated freshness, and a booking step that survives one supplier failing mid-transaction.

Frequently Asked Questions

Node questions we get on every call

What engineering leads ask before committing a backend to Node. Something not covered? Speak to a Node developer.

Node suits work dominated by waiting: API layers, realtime services, streaming, and anything stitching several systems together. One language across client and server also removes a whole class of handoff between teams. It is the wrong choice when the work is CPU-bound — image and video processing, heavy numerical or cryptographic jobs, anything that holds the loop for tens of milliseconds — because while that runs, every other request in flight waits behind it. The usual answer is not to abandon Node but to move that one piece to a worker thread, a queue, or a service in a runtime built for compute.

Open for new projects

Tell us what you're
trying to build

The problem, who it's for, and where you are now. That's enough for us to come back with something useful.

24hTypical Reply

Email

hello@aryavos.com

HQ

Noida, India & New York, USA

What happens after you send it

A developer reads it, not an auto-responder. Expect questions about scope and constraints first, then a suggested way to start.

Tell us about the project

Rough is fine. The problem, roughly where you are, and what finished looks like.

Service Needed

Usually answered within one business day · No mailing list, no sales sequence