$ whoami
maya reyes — full-stack engineer, mern specialist, lisbon
Full-stack systems that hold up in production.
Five years turning product specs into MongoDB schemas, Express APIs, React interfaces and Node services that stay online after the demo ends.
What I actually own at each layer
Four letters, four different jobs. This is the ledger, not the buzzword grid.
| layer | owned here |
|---|---|
| MongoDB | schema design & indexing — document shape, compound indexes, aggregation pipelines that don't scan the collection. |
| Express | REST & auth middleware — route contracts, request validation, session and token handling. |
| React | state & component architecture — data flow that doesn't re-render the whole tree on every keystroke. |
| Node | queues & deployment — background jobs, CI, the process that keeps running at 3am. |
Selected work
Three shipped systems, formatted the way I actually track them — as a log, not a gallery.
a7f3c1e ledger-sync Cut month-end reconciliation from 3 days to 40 minutes.
problem
Finance teams were reconciling bank feeds against internal ledgers by hand, in spreadsheets, once a month — every mismatch found a week too late.
result
Now running at 12 mid-market companies. Reconciliation that took three days of an accountant's time now finishes itself in 40 minutes, unattended.
architecture
screen
2b9d40a routewise Reduced route-planning time by 68% across a 40-vehicle fleet.
problem
Dispatchers were building next-day routes manually against a paper map and a gut feeling, re-planning by phone every time a driver ran late.
result
Route plans that took 45 minutes to build now take 14. Late-day re-routing runs live, from the same optimizer, on the dispatcher's own screen.
architecture
screen
9e17f88 signalboard 2.4M events/day at sub-200ms dashboard refresh, p95.
problem
Support leads needed queue health and agent load on screen in real time, not in a report that ran at 6am against yesterday's numbers.
result
Now the system this whole site's architecture section is about — see below.
architecture
screen
// zoom: signalboard
One dashboard, four hops, no dropped frame.
react api gateway
node / express pub/sub
redis db
mongodb, sharded
signalboard's clients hold a websocket to a Node/Express gateway that fans every event out through Redis pub/sub before it lands in a sharded MongoDB cluster — the path that lets 2.4M events a day resolve into a chart update in under 200ms at p95, on a support floor that is watching it live.
currently taking one new contract for Q4 2026 / lisbon, UTC+1 / replies inside a business day, usually a few hours
Send the spec
Tell me what you're building. I'll reply with questions, or a plan.