Cost intelligence
Local-first cost intelligence for personal bank exports: exact money arithmetic, encrypted storage, and a hard privacy boundary.
- Role
- Author
- Context
- Personal
- Capabilities
- Data engineering, Security and access control
Overview
Personal bank exports are useful and radioactive. This prototype keeps them on the machine: exact money arithmetic (no floating-point “almost”), encrypted storage, and a hard line against sending the file to a model or a host.
I am building it alone. The GitHub description is the source.
Problem
Most personal-finance tools want the feed. I wanted a local read of exports I already have, with arithmetic I can trust, and no screenshot of a statement ever leaving the disk as “product evidence.”
Current state
Prototype, updated 2026. Private repository, not linked. Visibility is limited so the page can exist without becoming a data dump.
Limitations
A local tool is not a bank, a budget coach, or a production fintech. No balances, no merchant lists, no “I saved X.” If this page ever grows a screenshot, that is a bug.