fairsplit

Group expenses often lead to messy spreadsheets or reliance on third-party apps that mine your data. FairSplit provides a local, file-based way to track shared costs for trips, flatmates, or events without external accounts or API keys.

What it does

• Expense tracking records who paid for what and how to divide the cost among group members.
• Multiple split types handles equal splits, exact amounts, proportional shares, or percentages.
• Settlement optimization calculates the minimum number of payments required to zero out all debts.
• Currency management supports a home currency per group with optional exchange rate lookups for foreign expenses.
• Data export generates Markdown or CSV summaries for sharing or record-keeping.

How it works

1. Initialize a group by specifying a name, home currency, and the names of all participants.
2. Add expenses by providing the payer, amount, and the desired split logic for the group.
3. Review balances to see the net position of every member at any time.
4. Settle up to generate a specific plan of who should pay whom to close out the ledger.

Frameworks & tools

The skill uses a Python 3.8+ script relying solely on the standard library. Data is stored locally in JSON files, requiring no external databases or cloud services.

Why this beats prompting it yourself

LLMs frequently make arithmetic errors or rounding mistakes when calculating splits and settlements. This skill offloads all math to a tested script using integer minor units, ensuring every cent is accounted for and balances always sum to zero.

Use cases

• Manage shared household bills and rent among multiple flatmates.
• Track group spending during a vacation and settle up at the end.
• Record shared costs for a one-off event like a wedding or group dinner.
• Export a trip's financial history to a CSV for long-term archiving.

Known limitations

Does not move real money or link to bank accounts. Currency exchange lookups require outbound network access and may fail in restricted environments. Split amounts must sum to the total exactly.