Chartly
Mobile-first PWA that answers two questions: how long will my money last
this month? and, for rideshare and delivery drivers, how much do I really
make per hour? — counting real kilometres with the phone's GPS.
Live: https://desempleo-inky.vercel.app
Stack: Next.js 16 (App Router) · React 19 · TypeScript · Tailwind ·
Supabase (Postgres + RLS, magic-link and Google auth) · web-push ·
pg_cron + pg_net · Leaflet · Vitest + Playwright · Vercel
What it does
Two kinds of people use it, and the navigation adapts to each
(Hoy · Cuentas · + · Jornada or Métricas · Más).
Everyone — money in order
- Quick expense in two taps from the + button: how much, on what.
- Runway: a day-by-day projection of the balance until the end of the
month, showing which bill takes you to zero first.
- Bills due, recurring monthly expenses, wallets, multi-currency with live
exchange rates (ARS, USD, EUR, VES, CLP, MXN, COP, BRL…).
- Monthly budgets per category, warning at 80%.
- Receipt capture: share a payment screenshot to the app and an LLM fills
in amount, merchant and date (daily cap per user; the image is never stored).
Drivers and couriers (Uber, Rappi, Didi, PedidosYa…) — the Jornada tab
- GPS trip tracking: one button to start, one to stop. Real km and time,
with GPS noise and jumps filtered out, added to the day's shift.
- Auto-start: optionally, the trip starts by itself when the phone is
moving faster than walking (on any screen, while Chartly is open).
- Heatmap of the zones you drive the most (7 / 30 / 90 days).
- Real earnings: payouts minus fuel, minus vehicle wear per km (with a
calculator), minus a tax reserve — per hour and in USD.
- Daily and weekly goals that spread the week's target across strong and weak days.
Works without signal: entries logged offline queue on the phone and sync
when connectivity returns; the app shell opens offline.
Also: agenda with push reminders, shared Trello-style boards, CSV export,
download all my data and delete my account.
Architecture
Browser (PWA) Vercel (Next.js) Supabase
───────────── ──────────────── ────────
Server Components ───────────────► SELECTs with the user's session ──► Postgres + RLS
Client Components ─── inserts/updates directly with the anon key ───► (RLS is the
security layer)
Service worker: push, offline cache
OfflineSync: queue → upsert by id
GPS: watchPosition → lib/geo ──────────────── rpc save_gig_track ───► gig_tracks
/api/share → Gemini / Claude
/api/push/* → web-push ◄─── pg_cron + pg_net
/api/account (delete / export)
/api/log → Vercel logs
- RLS is the security boundary. Every table is scoped to
auth.uid();
routes that need more (cron, invitations, account deletion) use the service
role on the server only.
- Business logic lives in
src/lib as pure functions (runway, GPS
distance, real earnings, budgets, dates, amount parsing, offline queue) and
is unit-tested in isolation.
Technical decisions worth reading
A scheduler inside the database. Vercel's Hobby plan can't run cron at
minute resolution, and scheduling reminders from the frontend depends on the
app being open. pg_cron fires every minute inside Postgres, pg_net POSTs to
/api/push/cron with a shared secret, and the handler sends due reminders
through web-push. Trade-off: two extensions and a secret to rotate, in
exchange for minute resolution without a paid plan or a separate worker.
GPS distance you can trust. Summing raw readings turns an 80 km day into
110 km: a parked phone jitters 5–30 m and occasionally jumps hundreds of metres.
lib/geo.ts drops readings with poor accuracy, ignores moves smaller than the
noise (without moving the anchor, so slow progress still adds up), rejects
impossible speeds, and adds a straight line when the signal comes back.
Saving is a single idempotent RPC, so a retry on a flaky connection never
double-counts kilometres. Auto-start (lib/motion.ts) looks at a two-minute
window and only fires when the movement holds without its first and without
its last reading, so a single GPS jump never starts a trip; the tracker lives
in a provider in the app layout, so it keeps measuring outside the Jornada tab. The heatmap is aggregated in Postgres
(gig_heat_cells) instead of shipping thousands of points to the phone.
Offline first where it matters. Drivers log trips in places with no data.
Failed inserts go to a local queue with a client-generated id; OfflineSync
flushes it with upsert … ignoreDuplicates when the connection returns, and
resolves the shift id at send time.
The user's day, not the server's. Vercel runs in UTC: after 9 p.m. in
Argentina it is already "tomorrow". Everything that depends on today
(shifts, runway, today's agenda, greeting) goes through lib/dates.ts with
the user's time zone.
Amounts from any country. "$12.345,67", "$1,234.50", "$ 15.990"
(CLP) and "Bs. 1.234,56" all parse correctly (lib/amount.ts) — both for
LLM output and for what users type.
This is the beginning of the README. Read the rest at the original. Read the full README ↗
