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Juno

The new version of my finance app: a local-first personal and household tracker for the Linux desktop and iPhone, with optional sync between them.

My partBuilt solo

GitHub — juno ↗Read the write-up →

In short

A personal and household finance tracker for the Linux desktop and iPhone, built in Flutter. It is local-first, with optional Supabase sync between devices, and it is the new version of my earlier finance app, REE.

What it is
A local-first personal and household finance tracker for the Linux desktop and iPhone.
Why it matters
Tracking money only works if logging is quick enough to keep up, and a shared household needs to see what is personal and what is shared. Juno is built around both: fast entry everywhere, and a Personal or Household mark on every entry.
My part
I built it on my own: the app, its sync engine, its design system, and its tests.

Step by step

  1. 1

    Log

    Expenses, income, and transfers across accounts, each marked Personal or Household. On desktop, N opens a new entry; on iPhone, Siri, Shortcuts, Back Tap, the Action Button, and a home-screen widget log without opening the app.

  2. 2

    Import

    A bank CSV comes in with its columns guessed, categories learned, already-seen rows skipped, and an undo. Excel workbooks and Notion CSV exports import too, and export writes everything back out to CSV.

  3. 3

    Plan

    Monthly budgets per category or scope, savings goals with contributions, and recurring entries that log themselves on their due date, with a reminder on the day and budget alerts at 80% and 100%.

  4. 4

    Understand

    Where the money went this month, what changed against the same point last month, six-month trends, top places, recurring costs, totals per tag, and net worth over twelve months.

  5. 5

    Sync

    Optional Supabase sync with row-level security. Every row carries an update time and a soft delete, so a device pushes what changed and pulls what it missed.

From the project

Juno’s home screen with demo data: the month’s spending, budgets, and accounts.
The home screen, with demo data.
Juno’s Insights screen on the desktop with demo data: the month’s spending by category, a day-by-day calendar, and what changed this month.
Insights on the desktop, with demo data.
Juno’s Plan screen on the desktop with demo data: four monthly budgets with what is left in each.
Budgets in Plan.
Juno’s home screen on iPhone with demo data: the month’s spending, safe to spend today, and personal versus household spending.
The home screen on iPhone.
For engineersHow it is built, its limits, and its keywords.

How it works

A Flutter app on drift tables, with every read and write going through one Ledger layer. Sync is optional: each round pushes local changes to Supabase and pulls server changes since a per-table cursor, with last-write-wins conflicts and deterministic ids so two devices converge instead of duplicating. On iPhone, Siri, Shortcuts, Back Tap, and the Action Button drop entries into a shared inbox that Juno imports on its next launch.

Limits

  • Sync conflicts resolve last-write-wins, so if two devices edit the same entry before syncing, the later edit is the one kept.
  • Exchange rates are the ones you set: totals stay in USD, and each entry keeps the USD value it was logged at.
  • The iPhone app is built on a Mac and installed from Xcode.

Keywords

  • personal finance
  • household budget
  • Flutter
  • local-first
  • Supabase sync
  • iOS App Intents

Read the write-up →

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