Backend Developer Cover Letter Example

Orderbase processes roughly 50k transactions per hour based on your engineering blog post from March — that is the scale where naive database locking strategies start showing up as latency spikes in your p99. I have spent two years at this exact scale and I know where the bodies are buried.

At Finlo I redesigned the settlement reconciliation service to handle 80k events per hour without degrading p95 API latency. The root cause was synchronous database writes blocking the event loop — moving to an async write-behind cache with idempotency keys and periodic reconciliation reduced p95 from 420ms to 38ms. The change also made the system resilient to partial write failures that had been causing silent data inconsistencies for six months.

I design APIs for longevity: versioned endpoints, strict backwards-compatibility contracts, and client-observable deprecation timelines. At Finlo I maintained a public API across four major versions over three years without a single forced migration. The discipline that makes this possible is writing the breaking-change impact analysis before the PR, not after.

I work in Go and Python, with PostgreSQL and Redis as my primary data layer. I write async design documents before I write code, which I have found reduces review cycles and architecture surprises significantly. Happy to share an example document from a recent project if that gives you useful signal on how I think.