Built by someone who needed it first.

j17 started as internal infrastructure. I was building systems that needed complete audit trails, dispute resolution, and the ability to reconstruct any past state. The kind of problems where "just use Postgres" leaves you debugging at 2am, cross-referencing logs, hoping you can figure out what actually happened.

I looked at the options. Kurrent (EventStoreDB) is powerful but expensive, production clusters run $800-2,000/month. Building it yourself means Kafka, Redis, custom projections, and months of engineering time you'll spend maintaining forever. So I built what I needed: event sourcing that's simple to use, cheap to run, and doesn't require a PhD to operate.

Once it was working, I realized other teams had the same problem. So I spun it off.