Senior Software Engineer
James Chen
I build systems that scale — from zero to millions of users.
Engineering field notes01 — 05
Payment Processing Engine
- Context
- Stripe needed to handle 10x payment volume during peak events without increasing latency.
- Work
- Re-architected the core processing pipeline using Go, introducing async job queues and intelligent retry logic with exponential backoff.
- Outcome
- Reduced p99 latency by 60% and processed $2.3B in transactions during the 2023 Black Friday peak with zero downtime.
Edge Cache Invalidation System
- Context
- Cloudflare cache invalidation was causing 200ms+ delays for time-sensitive content updates.
- Work
- Built a distributed invalidation system using consistent hashing across 200+ edge nodes with sub-10ms propagation.
- Outcome
- Reduced cache invalidation time from 200ms to 8ms globally, serving 500B+ requests per month.
Internal Developer CLI
- Context
- Engineers at Stripe spent 45 minutes average on environment setup per new service.
- Work
- Built a CLI tool that scaffolds new services with full CI/CD, monitoring, and documentation in one command.
- Outcome
- Reduced new service setup from 45 minutes to 4 minutes. Adopted by 200+ engineers within 3 months.
The person behind the work
Senior Software Engineer with 7 years building distributed systems at scale. Previously at Stripe and Cloudflare. I specialise in backend infrastructure, developer tooling, and performance optimisation. Currently open to senior IC and staff engineering roles.
2021 – 2024
Senior Software Engineer — Payments Infrastructure
Stripe
- Led re-architecture of payment processing pipeline handling $50B+ annually
- Mentored 6 junior engineers, 4 of whom were promoted to senior within 18 months
- Reduced infrastructure costs by 30% through query optimisation and caching strategy
2018 – 2021
Software Engineer — Edge Infrastructure
Cloudflare
- Built cache invalidation system serving 500B+ requests per month
- Contributed to open-source Rust networking libraries with 12k+ GitHub stars
- On-call rotation lead for global edge network with 99.99% uptime SLA
Specialised in high-throughput backend systems with a focus on reliability and developer experience.