Skip to content
Mai Trinh
On holdOn hold — Backend foundation completed

CapFlow — Private Finance & Investment Tracker

A privacy-first personal finance and investment tracking project designed for offline use and end-to-end encrypted sync. Product specifications, security design and backend foundation are complete; development is currently paused.

Role
Product owner, architect and backend developer
Platform
Backend (mobile and web planned)
Period
2026

Project overview

Product
An app concept for recording cash, holdings, savings goals and an investment journal, with exact amounts and honest gaps instead of estimates.
Why it exists
CapFlow explores an end-to-end encryption design intended to prevent the server from reading sensitive financial content.

My role & contributions

Product specification with acceptance criteria, financial domain and ledger design, end-to-end encryption design with a proof of concept, sync protocol, and the FastAPI + PostgreSQL backend foundation.

Challenges & solutions

  1. Technical challenges

    Keeping money exact and consistent across offline devices whose data the server cannot read.

    Impact

    Design documents, test fixtures and a backend foundation are available for further development; mobile and web clients have not been built.

Architecture & technologies

Technologies

  • Python
  • FastAPI
  • SQLAlchemy
  • Alembic
  • PostgreSQL
  • Docker
  • pytest
  • mypy

This project demonstrates

  • Backend Development
  • Requirements Analysis
  • Offline Support
  • Authentication

Current progress

  1. Product specification

    Done
  2. Security and sync design

    Done
  3. Backend foundation

    Done
  4. Mobile and web clients

    Upcoming

Have a similar project in mind?

Tell me about your product or challenge, and we can discuss how I can help.

Work With Me