Notes

Engineering notes

Write-ups of problems I've worked through in backend systems, multi-tenant SaaS, auth, and AI products. Each one is written so you can apply it to your own codebase.

• 11 Oct 2026 · 2 min read

  One missing WHERE clause away from a data leak

  Every multi-tenant app trusts developers to remember tenant_id on every query. Here's how to make Postgres enforce it instead, in about 15 lines of SQL.

  BackendSecurity

• 9 Oct 2026 · 2 min read

  Your RAG demo works. Then someone uploads a 240-page PDF.

  Chat-with-your-docs is magic with a 2-page file and falls apart with a real one. The fix isn't a better model; it's the boring pipeline around it.

  AIBackend