05Case studies

The decisions, not the feature list.

Each one covers the constraint that shaped the design, the architecture that followed, how it was deployed and observed, and the parts I would rebuild.

Studies: 3
Depth: 11 - 14 min each

Payments architecture14 min

Moving money across a border that does not want to cooperate

How a remittance backend keeps a transfer honest across two currencies, four mobile money networks and an unreliable phone connection.

Express.jsMongoDBPaydunyaSocket.IO

Scalability & storage12 min

Designing for the last hour before the deadline

A contest platform where nearly all traffic arrives in a two-hour window, at photograph file sizes, and the deadline cannot move.

Next.jsExpress.jsAmazon S3Agenda

Distributed systems11 min

Real-time messaging that survives being offline

Building a cross-continent artist network where two people are almost never online at the same time.

Next.jsExpress.jsMongoDBSocket.IO