Diffractt

We're building Diffractt for households managing different pay schedules, variable income, or salary alongside self-employment. It connects paycheck, monthly, and annual views so an income model does not have to live in a separate spreadsheet.

The app is in open beta. Free tax and paycheck calculators are also available without an account.

Built with Codex and Claude using Python/FastAPI and Postgres, with implementation, review, and testing kept as separate steps. All code was produced by AI, with the founder directing the product. The practical challenge is finding time to build alongside a full-time job while still deciding what belongs in the product and checking the results.

Submitted by the Diffractt team. Feedback from household spreadsheet users is welcome.