Kova Checkout
A rebuilt checkout for a B2B supplies shop that loads in about a second and stopped paging the engineers on call.
client
Kova Supply
role
Lead engineer, front end
year
2025
stack
Next.js · Stripe · Playwright
01 / problem
Kova Supply’s checkout was a five step form on top of a cart service written in 2015. It took 2.8 seconds to load at the 95th percentile, broke whenever the payment provider changed a field, and woke someone up most weeks.
02 / approach
I rebuilt it as one Next.js route whose steps render on the server, moved card entry to Stripe’s Payment Element and covered every step with Playwright tests that run against a staging copy of the cart. The old flow stayed live behind a flag until the numbers were clear.
03 / outcome
The new checkout shipped in six weeks. Load time at p95 dropped from 2.8s to 1.1s, conversion rose 9% in the first quarter, and nobody on call has been paged about checkout since launch.
1.1s
p95 load time, down from 2.8s
+9%
Checkout conversion in the first quarter
