Solomon Ajayi is a software engineer and the founder of Whocomply. He has built double-entry ledger systems, workflow engines, and payment infrastructure processing millions of dollars in transactions, with fintech work at OneLiquidity and insurance technology at Curacel. He created Fintech Lab to teach engineers the money-movement systems he learned to build in production.
Fintech Lab is the engineering school for fintech that I wish I'd had when I started: a real Postgres-backed double-entry ledger you can post to, 85 lessons on the patterns behind ledgers, payments, lending, risk, and scale, and replayable incidents from the moments those patterns got tested in public. Everything here is written from building these systems, not from a textbook.