Version 1.3

About MyMon

MyMon is a small personal expense tracker built for clarity, not for completeness. It answers one question well: what did this month cost me, and where did it go?

What it does

  • Logs an expense: amount, category, date and an optional comment.
  • Shows one month at a time: the total, where it went, and last month beside it.
  • Steps back through earlier months, and charts them.
  • Searches everything you logged, and exports the lot as a spreadsheet.
  • Shares a ledger in a group, with comments, narrowed by person or category.
  • Rings a bell — and your phone, if you ask — when somebody invites you or comments.

The rules

  • An amount is at least 0.01 and never negative.
  • A date is never in the future, and not more than 20 years back.
  • An expense can be corrected later, and a deletion can be undone.
  • Months are plain calendar months — no closing, no salary cycles.
  • The seven categories are fixed, and one of them is Other. They cannot be added to: each colour was chosen and checked twice, once against white and once against black, and an unchecked one would walk straight into that set.

Not here

  • Income, refunds and loans — not yet
  • A monthly limit, and expenses that repeat — not yet
  • Dividing a group total per head, or who owes whom. Not an omission: a group answers what was spent together, and that is the whole of it.
  • Custom categories — see the rules

How groups work

A group is a few people and a ledger they all write into. A group expense is always a row of its own — never a window onto your personal list. Either you type it straight into the group, or you copy one of your own across, and from that moment the two are independent: changing one leaves the other alone.

This is why nothing of yours can land in a group by accident, and why the database never has to show anybody else your own expenses. Only the group's owner can invite or remove people, only the person who wrote an entry can change or delete it, and leaving a group does not take your entries out of it — if five people split a trip, the total still has to be the total.

Until you accept an invitation, all you can see of a group is its name.

Where your data lives

Your expenses are stored in a database, under your account, so you see the same numbers on your laptop and on your phone. Clearing your browser no longer costs you anything.

You sign in with your Google account. MyMon never sees, asks for or stores a password — Google confirms who you are, and that is all we get.

The database decides who may read what, not the app in your browser. Your own expenses are yours alone. What you put into a group is readable by the people in that group, and by nobody else — including your name, which other people only ever see once you share a group with them.

What changed

The ones worth stopping at, newest first. MyMon is written in the open, so every change — including the dozens of small ones not listed here — is on GitHub.

  1. 1.3 Friends, and a phone that rings. Add somebody once, and inviting them to a group is picking a name instead of remembering a username. Notifications reach your phone with MyMon closed.
  2. 1.2 Notifications. A bell in the corner that tells you when you are invited to a group and when somebody comments — and takes you straight to the thing it is about.
  3. 1.1.19 – 1.1.20 Groups. A shared ledger, invitations, comments, and the rules underneath that decide who sees what.
  4. 1.1.17 – 1.1.18 Log any day in the past, and take the whole lot away as a real spreadsheet.
  5. 1.1 Real accounts and a real database. The same numbers on the laptop and the phone.
  6. 1.0 One number, seven categories, and a month you can read at a glance — kept in the browser alone.

Ready when you are

Three fields and a date. That is the whole ritual.

Open the dashboard Start tracking