Built. Questioned.
Explained.

Stories from the systems I build.
Follow the decisions. Move the pieces. See what changes.

Subscriptions / Data modelling / Materialized views

History becomes the present.

Your database says 26. How did it get here?

How a SaaS product rebuilt subscriptions as a ledger of dated facts, and why it still stores one answer.

Subscriptions / Append-only ledger / Migration

By morning it was wrong. What do you store instead?

Three decisions behind a subscription rebuild: store facts, compute state, and cache one answer.