BudgetBuddy

A full-stack finance app: accounts, transactions with CSV import, monthly budgets, recurring bills that post themselves, and reports that explain where the money went — on desktop or phone, light or dark.

Most budgeting apps are either spreadsheets in disguise or subscription products that lock your data away. I wanted something calm to use every day, that handles the boring parts — recurring bills, categorising, month-end math — automatically.

1. 01

   One typed Hono API with an RPC client, so the frontend and backend can't drift apart; TanStack Query hooks per feature.

2. 02

   Store every amount as integer miliunits and format it in the user's chosen currency at the edge.

3. 03

   Design mobile-first: a collapsible sidebar on desktop, a bottom tab bar with a centre add button on phones, ⌘K everywhere.

• H-01

  Recurring transactions that don't drift

  Occurrences are computed from the start date by index, so a rule on the 31st goes Jan 31 → Feb 28 → Mar 31. A claim-then-insert step stops two tabs from posting the same bill twice.

• H-02

  Budgets with a safe-to-spend figure

  Monthly limits per category with progress, over-budget alerts, and how much you can still spend per day this month.

• H-03

  CSV import that forgives messy files

  Upload, map columns with previews, pick rows, choose an account. Dates and amounts like $1,234.50 or (45) are parsed and bad rows are flagged, not silently dropped.

• H-04

  Private by construction

  Every endpoint checks the signed-in user and verifies that referenced accounts and categories belong to them.