Backend engineer building payment systems that stay up

Own the ledger and settlement services of a payments platform processing 40M transactions a month across 9 European markets.

• Led the decomposition of the payment monolith into 14 event-driven services on Kafka, cutting deploy time from 45 minutes to under 8.
• Designed an idempotent settlement pipeline that reduced duplicate payout incidents from roughly 30 a month to zero over 18 months.
• Cut p99 authorization latency from 850ms to 210ms by introducing read replicas and a Redis-backed rate-limit tier.
• Mentor four engineers; two promoted to senior on the strength of systems they designed under this guidance.

Built order management and logistics APIs for a second-hand goods marketplace with 2.5M monthly active users.

• Rewrote the order state machine, eliminating a class of stuck-order bugs that had generated 400+ support tickets a quarter.
• Introduced contract testing across 20 internal services, cutting integration regressions found in production by 70%.
• Scaled the search indexing pipeline to handle a 6x listing-volume increase during the 2020 lockdown without added hardware.

Delivered backend systems for banking and insurance clients as part of a 12-person consulting team.

• Built a batch reconciliation engine for a regional bank that shortened the nightly close from 6 hours to 90 minutes.
• Automated the deployment pipeline for three client projects, replacing manual FTP releases with versioned CI builds.
• Ranked top performer in the 2016 internal review cycle out of 40 developers.

A Go library for embeddable double-entry accounting with strict invariant checks, used in three production fintech systems.

• Grew the project to 1,900 GitHub stars and 12 external contributors.
• Property-based test suite verifies balance invariants across 10,000 generated transaction sequences per CI run.

Quarterly meetup on distributed systems and platform engineering, averaging 120 attendees per session.

• Curated 16 talks over three years, including four first-time speakers coached from outline to stage.
• Talk "Exactly-once is a lie you tell twice" recorded 8,000 views.

Focus on operating systems, databases, and concurrent programming. Final project: a fault-tolerant message broker in C.