Gabriele Ferreri

Senior Full-Stack Engineer | React + TypeScript + Node.js | 25+ years building enterprise solutions | Sharing real technical experiences

[Gabriele Ferreri @megasoft1978]

@ashxhart That's the problem. Any smart quantization that keep most of the quality? I can use something like 11-12gb max I think. We can work together to see if it's possible if you like.

[Gabriele Ferreri @megasoft1978]

41 K8s nodes at 3% CPU. Monthly bill: $61.5K. One team right-sized to 17 nodes in 22 hours. Monthly bill: $13.5K. The fix was kubectl top + smaller instances + same labels.

#Kubernetes

[Gabriele Ferreri @megasoft1978]

A JS framework compiles your route handlers at startup using eval(). Sounds terrifying—until you see 2.4M req/s vs Express's 113K. The bottleneck was never your runtime.

#JavaScript

[Gabriele Ferreri @megasoft1978]

2026 benchmarks: Bun won 8/14 tests, Deno 5, Node 1. But Express on Bun ≈ Express on Node. Elysia on Bun: 2.4M req/s. Your framework is the bottleneck, not your runtime.

#JavaScript

[Gabriele Ferreri @megasoft1978]

SSE uses 60% less memory than WebSockets.

95% of "real-time" apps only need server→client updates. SSE does that in 3 lines with auto-reconnect built in.

OpenAI chose SSE for ChatGPT streaming. So should you.

#WebDev

[Gabriele Ferreri @megasoft1978]

Our Docker image: 1.2GB → 120MB. Build: 8 min → 45s.

Multi-stage builds: use Alpine for production, keep build tools in a separate stage. One Dockerfile change, 90% smaller.

#Docker

[Gabriele Ferreri @megasoft1978]

I deleted 12 npm packages. Zero functionality lost.

structuredClone() replaces lodash.cloneDeep
crypto.randomUUID() replaces uuid
Intl.DateTimeFormat replaces moment

Your browser already has it.

#JavaScript

[Gabriele Ferreri @megasoft1978]

TypeScript's compiler is being rewritten in Go.

10x faster type-checking. A 40s build drops to 1.3s warm.

Your slowest CI step is about to disappear.

#TypeScript

[Gabriele Ferreri @megasoft1978]

We replaced MongoDB with PostgreSQL JSONB. Same queries, 40% lower infra cost.

GIN-indexed containment queries on 2M rows: 3-8ms.

One database instead of two.

#PostgreSQL

[Gabriele Ferreri @megasoft1978]

I removed 47 console.log calls from our API. Response time dropped 22ms.

console.log serializes objects synchronously and blocks when stdout is piped.

Switch to Pino: 5x faster.

#NodeJS

[Gabriele Ferreri @megasoft1978]

ES2024: Promise.withResolvers()

Before:
let resolve;
const p = new Promise(r => resolve = r);

After:
const { promise, resolve, reject } = Promise.withResolvers();

One line. No hoisting. No callbacks.

Shipped everywhere.

[Gabriele Ferreri @megasoft1978]

Stop using JSON.parse(JSON.stringify()) for deep copy.

Use structuredClone():

const copy = structuredClone(obj);

✅ Handles Date, Map, Set, circular refs
❌ JSON breaks Dates, drops undefined, throws on cycles

Native. 98% support.

[Gabriele Ferreri @megasoft1978]

AbortController cancels more than fetch():

✅ fetch requests
✅ addEventListener (auto-remove!)
✅ AbortSignal.timeout()
✅ Readable streams
✅ Node.js fs ops

One ctrl.abort() cleans up everything.

Most underused JS API.

[Gabriele Ferreri @megasoft1978]

Docker layer order = build speed.

Wrong:
COPY . .
RUN npm install ← re-downloads all

Right:
COPY package*.json .
RUN npm ci ← cached unless deps change
COPY . .

One layer changes → all after it rebuild.

Order by change frequency.

[Gabriele Ferreri @megasoft1978]

React 19's use() API is stable now.

const user = use(userPromise);

It's not a hook — it works in conditionals.
✓ Unwrap promises in render
✓ Read context anywhere
✓ No useState/useEffect

Requires Suspense. Ships with React 19.

[Gabriele Ferreri @megasoft1978]

Module augmentation: extend types you don't own.

declare module 'express-serve-static-core' {
interface Request {
user?: { id: string };
}
}

Full type safety. No forking. No `any`.

Official TS feature since v2.

[Gabriele Ferreri @megasoft1978]

Blue-green deployment:

Two environments: Blue (current), Green (new)

1. Blue = production
2. Deploy to Green
3. Test
4. Switch traffic
5. Rollback if needed

✅ Zero downtime
✅ Instant rollback

Cost: 2x infrastructure during deploy.

[Gabriele Ferreri @megasoft1978]

Health checks prevent downtime:

✅ Liveness: Is process alive?
✅ Readiness: Can handle requests?

app.get('/health/ready', async (req, res) => {
await https://t.co/3tUmPqhsFJ();
res.send('OK');
});

Load balancers need this. Return 503 when unhealthy.

[Gabriele Ferreri @megasoft1978]

0.1 + 0.2 = 0.30000000000000004

Floating point precision issue.

Solutions:
✅ Store cents, not dollars
✅ Math.round((n * 100) / 100)
✅ Use decimal.js library
✅ Compare with epsilon

Never === with floats.

For money, use integers.