Cole Oliver Cofer
Summary
Senior Software Engineer and Tech Lead with eight years of experience building backend systems in Go, Java, PostgreSQL, Kafka, and Kubernetes. Leads a team of five on the trade booking platform at Apex, a clearing firm with $200B+ in assets under custody, and led its multiyear rewrite from a legacy Java stack into real-time Go services. Early and heavy adopter of agentic AI development who has made it part of how the team designs, ships, and recovers. Outside of work, builds and ships software end to end for the joy of it, including a Steam game and several iOS and watchOS apps.
Experience
- Trade Booking Rewrite: Led the multiyear replacement of the legacy on-prem trade booking system (Java, RabbitMQ, MongoDB) with real-time Go, PostgreSQL, Kafka, and gRPC services in the customer trading path, cutting trade confirmation from minutes or hours to milliseconds. Owned architecture and API design throughout. The new platform holds $1B+ in custody, serves 4 million+ requests a day as traffic migrates off the legacy system, and meets FINRA, SEC, and SOC requirements for data retention, PII, multi-region disaster recovery, and daily reconciliation reporting.
- Scalability Initiative: Drove a cross-team scalability initiative for Apex's clearing platform and owned our team's part end to end: raised booking throughput 25x (200 to 5,000+ trades/second) and cut response times 40% through PostgreSQL query optimization, read replicas, parallelized downstream calls, and async processing.
- Agentic Development: Established the team's agentic development workflow and used it to reach feature parity with the legacy platform: ported a COBOL library to native Go, wrote end-to-end tests that run daily against live environments, and built a harness that submits trades through both systems and diffs the results. Maintain custom Claude Code skills, restructured service docs so agents can read them directly, and keep teammates current on the tooling.
- Technical Leadership & Mentorship: Lead a team of five and serve as the go-to engineer for systems handling 20 million+ requests a day, owning API design, architecture, and on-call coordination while still shipping code. Mentor interns and junior engineers through hands-on pairing, several of whom have since grown into senior engineers.
- Incident Tooling: Built tooling that generates correction files for mis-booked trades and made it self-service for the operations team, replacing hand-built CSVs and one-off scripts, cutting incident recovery time 50%, and giving engineers back hours every week.
- Developed and maintained backend microservices for an e-commerce platform using C# and .NET.
- Built comprehensive automated test suites using Cypress and AVA, improving deployment confidence.
Independent Projects
A mix of hand-written and agent-built work. Radish and Beardsman's Bakery were built entirely with coding agents using a spec-first workflow: detailed upfront design, autonomous implementation and review agents, then heavy testing. More at colecofer.com.
Education
Skills
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