Node.js
Event-driven, non-blocking I/O for API gateways, real-time applications, and BFF layers. The natural choice for connection-heavy workloads.
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Event-driven by default
Node.js runs JavaScript on the server, and its event loop makes one deliberate trade: a single thread, nothing blocking, every I/O operation asynchronous. That suits services whose work is coordination, holding thousands of open connections, calling databases and downstream APIs, assembling responses, which is what most API layers spend their time doing.
It is the runtime we choose when a TypeScript team should own the whole path from interface to integration, and the natural home for real-time workloads: WebSocket fan-out, live dashboards and notification delivery all sit on the same event loop the APIs use.
The platform has consolidated. ESM modules, built-in fetch, a native test runner and watch mode have folded what once required third-party packages into the runtime itself, thinning the dependency tree a service carries.
The event loop is also the model's boundary. Sustained CPU-bound work, transcoding, heavy computation, large in-process data processing, blocks every connection the process holds, and worker threads stretch that only so far. Workloads shaped like that belong in Go or Java, with Node.js keeping the coordination layer in front of them.
Node.js was used by 48.7% of respondents to the 2025 Stack Overflow Developer Survey.
Each even-numbered Node.js release enters long-term support in October and is maintained until roughly three years after its initial release.
- API Gateways
- Real-Time Apps
- Serverless Functions
- BFF Layers
Our Node.js capabilities
API services with Fastify & NestJS
We build Node.js APIs on Fastify where throughput and a small surface matter: JSON Schema validates every request and response at the boundary, and the OpenAPI document is generated from those same schemas. NestJS is the choice when a large team needs enforced structure, with modules, dependency injection and decorators making a big codebase navigable at the cost of some ceremony. Both sit behind the same observability and deployment discipline, so the framework choice stays a per-service decision.
- Fastify
- NestJS
- OpenAPI
Real-time & WebSocket systems
Persistent connections fail in ways request-response traffic does not, so the failure modes are engineered first: reconnection with backoff and resume, backpressure when a consumer falls behind, heartbeats that tell a dead socket from a quiet one. Fan-out beyond a single process runs over Redis pub/sub, letting the fleet scale horizontally while each client keeps one connection. Server-sent events carry the cases where one-way push is enough.
- WebSocket
- Socket.IO
- SSE
Serverless & edge deployment
Node.js is the runtime serverless platforms support first, and we deploy it across AWS Lambda and Cloudflare Workers with each platform's constraints priced in. Cold starts are held down by small bundles and lazy initialisation; database access goes through pooled proxies, because a thousand short-lived function instances cannot each hold a connection. SST keeps the infrastructure definition in TypeScript beside the application code it deploys.
- AWS Lambda
- Cloudflare Workers
- SST
Why Adaca for Node.js?
Enterprise API layers
BFF services and API gateways between React front-ends and Java or .NET backends.
Event loop expertise
Event loop phases, microtask queues, worker threads, and diagnostics via clinic.js.
Real-time delivery
WebSocket notification systems with reconnection logic, backpressure handling, and Redis pub/sub scaling.
Observability & reliability
OpenTelemetry, Pino structured logging, and health checks reporting event loop lag and memory usage.
Shared TypeScript stack
Node.js engineers who also build the React front-ends. One team, one language, shared types.
Serverless architecture
Lambda and Workers with cold start optimisation, connection pooling, and cost modelling for variable traffic.
How We Staff It
Node.js briefs are usually staffed from the same pool as our TypeScript and React work, because the runtime is most often chosen to keep one language across the stack. A brief for pure back-end work, API layers, real-time systems, integration services, draws on the same engineers with the balance shifted server-side.
Where a role needs specific depth, event-loop diagnostics, WebSocket infrastructure, serverless cost tuning, we match on that history rather than on years of JavaScript alone. Engineers work in your repositories and pipelines, to your working day.
Common Questions
Node.js or Go for a new backend?
The split is by workload shape. A service that coordinates, authenticating requests, aggregating downstream calls, streaming responses, holding connections open, is the case Node.js was designed for, and a TypeScript front end strengthens it: one language and one set of types across the team. Go earns its place where the service computes rather than coordinates, where memory footprint is tight, or where a single static binary simplifies deployment.
Many estates run the split rather than choosing once: Node.js at the edge of the system, Go or Java on the heavy paths behind it. We staff both sides of that line.
Is Express still a reasonable base, or should we move to Fastify or NestJS?
Express keeps working, and working systems do not need replacing on principle. The case for moving is specific rather than general: Fastify brings schema-validated requests and responses with materially higher throughput for API-heavy services, and NestJS brings enforced structure, modules and dependency injection, that large or rotating teams feel every day.
When a move is justified, it happens service by service as systems are touched for other reasons. A wholesale rewrite of working Express services rarely earns its cost.
Does AI-assisted development work well on a Node.js codebase?
Well, for reasons specific to the runtime. JavaScript and TypeScript form one of the densest public code corpora an agent can train on, and the Node.js API surface has been stable for years, so generated server code is rarely wrong about the platform itself. The weak point is the ecosystem around it: npm libraries move faster than any corpus, and an agent will confidently write against the version of a dependency it learned rather than the one in your lockfile.
The countermeasures are ordinary engineering discipline: a deliberately small dependency tree, lockfiles, TypeScript for the compile-time signal, and integration tests at the seams where library drift surfaces first.
We have a callback-era Node.js codebase. Will AI tooling help modernise it?
Yes, under supervision. The public corpus covers every era of Node.js, callbacks, promises, async/await, CommonJS and ESM, so agents read old code fluently and are effective at the mechanical work: promisifying callback chains, converting module systems, replacing abandoned dependencies with maintained ones.
The risk concentrates where idiom conversion changes behaviour, error propagation, unhandled rejections, code that depended on callback timing. We treat it like any refactor of untested code: characterisation tests on the paths being changed first, then the conversion lands in small, reviewable steps.
How fast can you stand up a Node.js team?
A shortlist usually reaches you within 48 hours of a brief, drawn from people we already employ or already know, with dedicated recruitment covering narrower needs such as WebSocket infrastructure at scale. Because Node.js shares a pool with our React and TypeScript work, a brief that starts as one back-end engineer can widen to a full-stack team without a second search.
Terms are three, six, nine or twelve months, agreed at the start, and engineers keep your working day.
Will you build in Node.js even if you would recommend something else?
Yes. If your platform is Node.js, we staff it and work to your architecture; the recommendation is made once, at the start, and stated plainly.
The usual disagreement is a CPU-heavy workload fighting the event loop. Where we see one, we will propose carving that path out to Go or Java while Node.js keeps the coordination in front of it, a bounded change that leaves the rest of the estate alone.