How Common Things works
Common Things is different from other finance apps: your data lives in your Google Drive, not ours.
See exactly what Common Things can access
No vague promises — here is the permission boundary, file by file.
Common Things wants access
Google permission request
✓ See and manage its own Drive files
Only files created by Common Things or opened with it.
✓ Read and write Google Sheets
Used for personal, Circle and shared group workbooks.
Browse every file in your Drive
You see every permission up front
Per-file Drive access manages app files. Sheets access keeps your personal and shared group workbooks in sync.
drive.file means Common Things can only see files it created — not your whole Drive. spreadsheets access is used solely for app workbooks.
1. Sign in with Google
We use Google OAuth with the per-file drive.file scope, without broad Drive browsing. We also request spreadsheets access so personal, Circle and shared group workbooks can sync. Common Things uses that permission only with its app workbook IDs.
2. Your personal workbook
On first sign-in, Common Things creates a Google Spreadsheet titled Common Things Personal — [Your Name] inside a Common Things folder in your Drive. This workbook has structured tabs for expenses, budgets, categories and sync logs. You can open it in Google Sheets at any time from the Settings page.
3. Group workbooks stay private
When you create a group (for flatmates, a trip, a household), Common Things creates a separate group spreadsheet. Your personal expenses are never shared with group members. Only the group workbook is shared with invited collaborators.
4. Local-first, works offline
Expenses you add are saved to your device immediately — even without a network connection. A small sync indicator shows Pending, Syncing or Synced status. When you're back online, changes flow to your Google Sheet automatically.
5. Split bills, settle up
Add a group expense and choose how to split: equally, by exact amounts, by percentage, or by custom shares. Common Things calculates the minimal number of payments needed to zero out all balances. Share the settlement summary via any app — WhatsApp, iMessage, email, or just copy-paste it.
6. Export and leave any time
Your data is already in Google Sheets — open it, copy it, export it as CSV, or simply stop using Common Things. There's no export lock or deletion fee. The Settings page has a one-tap Open in Google Sheets button plus full data-delete instructions.