Stripe

As an intern on the User Billing team, I designed and shipped a new event-driven way to charge merchants. I owned it end to end: I designed the architecture, built a new API backed by MongoDB, and tested and rolled it out in production.

It now handles 20,000+ fee jobs a day and bills 100,000+ merchants a month. Merchants used to get billed for fees about 3 days after their transactions. Now it's 1 to 2 hours.