Why Lyncost is a single SQLite file, not a hosted database

When we started Lyncost, the obvious path was a hosted Postgres instance and a sync API. We tried it for about two weeks in a prototype before throwing it out.

The problem wasn't performance — Postgres handles personal-finance-scale data without breaking a sweat. The problem was what it implied: your spending history would live on a server we operate, behind an account we could suspend, in a database we could lose. For an app whose entire pitch is 'this is private,' that's a contradiction we weren't willing to ship.

SQLite solved it in the most boring way possible. One file, on your disk, readable by any SQLite tool if we ever disappear as a company. Backups are a file copy. There's no schema migration that requires downtime, because there's no uptime to begin with — the database only runs when you do.

The tradeoff is real: no built-in multi-device sync, no server-side search across years of history without loading the file. We think that tradeoff is the right one for a tool that's supposed to outlive our roadmap.