settle: payments matched to invoices automatically
Matches incoming payments to invoices automatically. Clear matches are handled by fixed rules, and anything uncertain goes to a person to check.
The challenge
For every payment that reaches the bank account, someone has to work out which invoices it paid. One transfer covers three invoices, a customer pays part now and the rest later, a bank takes a fee on the way, and the reference says whatever the customer typed. Two invoices for the same customer can have the same amount on the same day.
What we built
A Python engine that handles exact matches, one payment for several invoices, part payments, overpayments and bank fees by fixed rules. Every match comes with a confidence score and a plain reason. An optional AI model only reads messy payment references and suggests invoices; the engine checks each suggestion against the open invoices, and anything uncertain goes to a review list instead of being guessed. At the end of every run, the engine checks that no money was lost or counted twice, and discards the result if it was. A browser app adds column mapping for CSV exports from accounting software, a run history and a password.
Project facts
- Type
- Our own product, source available (PolyForm Noncommercial)
- Technology
- Python
- FastAPI
- Pydantic
- Hypothesis
- SQLite
- Claude API (optional)
Result
Source on GitHub (v0.1.0): github.com/nagytamasgit/settle.
On heavily noisy generated test data, 97% of the matches it makes are correct; anything it can't decide goes to a person.
Building something like this?
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