Cashflow

live

A personal finance app that budgets from payday to payday, not the 1st to the 31st. Built solo, from schema to deploy.

role: Solo, design to deploy
frontend: React on Vercel
backend: NestJS, Prisma on Railway
data: PostgreSQL

Cashflow dashboard for the 25 Oct to 24 Nov pay cycle: RM 1,190.17 left to spend with 14 days to payday, a breakdown of commitments, spending, investment and savings against last cycle, recent transactions and savings goals.

the idea

Most budgeting apps reset on the 1st. Salaries don't. When pay lands on the 25th, a calendar-month budget splits one paycheck across two months and the numbers stop meaning anything.

Cashflow runs every budget on the pay cycle instead. The dashboard answers one question first: how much can I still spend before payday?

what it does

shared goals

Invite a partner to a savings goal and track who put in what. Only goals both people agree to share are visible to the other, and invites and accepts land in an in-app inbox.

In-app inbox showing that the partner accepted the Japan trip goal and a link request.

Savings page with two goals: an emergency fund at 34% and a Japan trip shared with a partner, showing how much each person has put in.

recurring entries

Rent, bills and salary post themselves on the day. You can see what's still to come this cycle, and pause or edit a rule without touching entries already posted.

works on your phone

The same dashboard on mobile, with a bottom tab bar for the five main pages.

Cashflow dashboard on a phone, with a bottom tab bar for dashboard, budget, transactions, investments and savings.

under the hood

The backend is where most of the work went.

React

web app · Vercel

NestJS API

auth · budgets · goals · scheduler · Railway

PostgreSQL

via Prisma

Resend

reset emails

cycle snapshots: Each pay cycle keeps a snapshot of its budget, so changing this month's plan never rewrites last month's.
versioned rules: Recurring rules keep their history, and a daily scheduled job posts what's due. Editing a rule only affects future entries.
auth that holds up: JWTs are invalidated after a password change, reset links are hashed and single-use, and login is rate-limited with per-account lockout.
partner sharing: Invitations, consent per goal and an inbox for events, so one person's data is never visible without the other agreeing.

← work