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Tally And Trace

A full-stack, type-safe financial management tool for personal and business finances

February 24, 2026QA In Progress

React · FastAPI · TypeScript · PostgreSQL · React Native · Redux Toolkit · TanStack Router · Supabase · Render · Vite · Expo · Sentry

A full-stack, type-safe monorepo for personal and business financial management. Features a React web frontend, a FastAPI backend, a shared TypeScript package, and a React Native mobile app (coming soon).

Project Overview

Tally And Trace was developed to solve our own need for a simple, flexible financial tracking tool that would replace our aging Google Sheet tracker. Existing solutions were either too complex, too expensive, or lacked the multi-entity support we needed to manage both personal and business finances in one place.

The Build (Seth)

  • Architected a monorepo structure with shared TypeScript package
  • Built React web frontend with TanStack Router and Redux Toolkit
  • Developed FastAPI backend with Pydantic v2 for type safety
  • Implemented PostgreSQL database with SQLAlchemy ORM
  • Created React Native mobile app foundation (Expo)
  • Deployed on Render with Supabase for database hosting
  • Wired Sentry error and performance monitoring across the API and web app — production-only, with request bodies, cookies, auth headers, and typed-input breadcrumbs scrubbed before send

The Break (Christine)

  • Test baseline for the cash-flow forecast engine, with CI gating on backend and shared-package suites
  • API endpoint validation and error handling
  • Multi-currency transaction testing
  • Data integrity and security audits
  • Performance testing for large transaction sets

Features

  • Multi-Entity Architecture: Manage personal and business finances under separate entities
  • Account Management: Cash, e-wallets, savings, checking, and credit accounts with multi-currency support
  • Transaction Tracking: Record income, expenses, and transfers with FX fields
  • Cash-Flow Forecast: Day-ordered running-balance timeline that surfaces the lowest point before payday and flags shortfalls — not just the reassuring month-end total
  • Mark Paid: Materialise a due entry into a real transaction, moving the account balance and rolling the recurring schedule to its next date
  • Budget Entries: Recurring income/expense items with configurable cadence — weekly, biweekly, semi-monthly, monthly, quarterly, semi-annual, and annual
  • Allocations: Savings goals, budgets, and period-based allocations
  • Wishlist: Prioritised wishlist items linked to categories and entities
  • Data Export: One-click JSON/CSV export of your entire dataset
  • Type Safety: Pydantic v2 on the backend, TypeScript everywhere on the frontend
  • Mobile App (coming soon): React Native (Expo) app with NativeWind styling

Tech Stack

  • Frontend: React, TypeScript, Vite, TanStack Router, Redux Toolkit, Tailwind CSS
  • Backend: FastAPI, Python 3.12, SQLAlchemy, Pydantic v2
  • Database: PostgreSQL (Supabase)
  • Mobile: React Native, Expo SDK 52, NativeWind
  • Deployment: Render (backend + frontend), Supabase (database)
  • Monitoring: Sentry — separate tally-trace-api and tally-trace-web projects, production-only, PII scrubbed before send
  • Shared: TypeScript package for type definitions and utilities

Screenshots

TallyAndTrace Dashboard TallyAndTrace Accounts View TallyAndTrace Transactions TallyAndTrace Light Mode

Related Posts

October 14, 2026 · Technical

From Entities to Owners: Reworking Tally & Trace

How Tally & Trace's projection engine grew from a pooled balance into card statements, spending wallets and loans, why shared 'entities' were replaced by single-owner records, tags and Drive-style shared accounts, and how every audit finding was reproduced before it was fixed.

Read more →

July 20, 2026 · Technical

Wiring Sentry Into a Finance App Without Leaking the Money

Adding error and performance monitoring to Tally & Trace — off by default, PII scrubbed on both surfaces, and Session Replay deliberately left switched off. It's live and reporting, but there's no war story yet: the interesting part is the config, not the outcome.

Read more →

July 19, 2026 · Technical

Which Account Comes Up Short: Per-Account Solvency in Tally & Trace

The cash-flow timeline used to pool every account into one balance. Now it routes each bill primary→overflow and tells you exactly which account can't cover what — plus credit-card statement modelling, hardened auth, and what's coming next.

Read more →

July 13, 2026 · Technical

The Month-End Total Lied: Modeling Cash-Flow Timing in Tally & Trace

Our budget app faithfully computed a reassuring month-end total — and was blind to the mid-month moment where the bills come due before payday. Here's how we reworked the forecast engine to model the one number the spreadsheet actually existed to compute.

Read more →

February 24, 2026 · Technical

TallyAndTrace: A Full-Stack Financial Management Solution

Building a type-safe monorepo for personal and business financial tracking to replace our aging Google Sheets

Read more →