How Common Things works

Common Things is different from most money apps: your records live in your Google Drive, not ours. Here is what actually happens, from signing in to opening the raw data.

1. Step 1

   Sign in with Google

   There's no separate Common Things password to create or remember.

   Technical detail

   Sign-in uses Google OAuth. Common Things stores an encrypted Google refresh token so your other devices can keep syncing without you signing in again on each one; you can revoke it at any time from your Google account.

2. Step 2

   Review the requested permissions

   Google shows you exactly what's being asked for before anything is granted.

   Technical detail

   Five permissions are requested: openid, email and profile for identity, drive.file for per-file Drive access, and spreadsheets to read and write workbook rows.

   drive.file cannot browse or list the rest of your Drive. The Sheets permission is broader — Google offers no per-file version of it — and Common Things restricts its own use to the workbook identifiers recorded for your account. The permissions breakdown covers each one in full.

3. Step 3

   Common Things connects your workbook

   It looks for an existing Common Things workbook in your Drive, and creates one only if there isn't one.

   Technical detail

   Your personal workbook is titled Common Things Personal — [Your Name] and sits inside a clearly named Common Things folder, with structured tabs for expenses, budgets, categories and sync state. You can open it in Google Sheets whenever you like from Settings.

   A Circle or Group gets its own separate workbook. Your personal expenses are never written into a shared workbook, and only the shared workbook is shared with the people you invite.

4. Step 4

   Add personal or shared expenses

   Keep an expense to yourself, or split it with a Circle or a Group.

   Technical detail

   Splits can be equal, by exact amounts, by percentage or by custom shares. Common Things works out the smallest set of payments that clears everyone's balance, and you can share that summary through any messaging app.

   People who don't use Common Things can still be included as guest members — they are labels used for the maths, and no account is created on their behalf.

5. Step 5

   Use it on your other devices

   Sign in anywhere and you're reading and writing the same workbook.

   Technical detail

   Expenses save to the device immediately, so adding one works without a connection. A sync indicator shows Pending, Syncing or Synced, and queued changes flow to your workbook when you're back online.

   Because devices share the workbook rather than a copy on our servers, a device that has been offline catches up the next time it connects. Signing in and anything that reads your Sheet do need a connection.

6. Step 6

   Open or export your records

   Open the sheet directly, or export CSV — any time, without asking us.

   Technical detail

   Your records are already in Google Sheets, so there is nothing to migrate if you stop using Common Things. Settings has a one-tap Open in Google Sheets button, CSV export for any period, and full deletion instructions for both the server record and the Drive files.