Hello from markz.io

Hi, I'm Mark Zhou — a senior backend engineer based in Auckland, New Zealand.

I've spent 15+ years building backend systems at scale: from high-traffic promotional platforms at Dianping sustaining 1000+ QPS, to distributed supply chain workflows at Meituan where reliability at 99.99% uptime wasn't optional, to a full SaaS platform I'm currently building end-to-end at Appzgate.

My core stack is Java/Spring Boot, Kafka, PostgreSQL, Redis, and AWS — though I've also been working in C#/ASP.NET Core and Go, and I'm genuinely interested in where AI fits into backend engineering (not as hype, but as a practical tool in the workflow).

What I'm building right now

Outside of work I'm building an NZ Open Banking Platform — a Spring Boot + Kafka backend implementing CDR/FAPI 2.0-style consent and account APIs, with a Spring AI + RAG compliance assistant running on AWS Bedrock. The RAG piece retrieves from real bank documentation rather than relying on LLM memory, which matters a lot when the subject is financial regulation.

It's the kind of project where the engineering decisions are interesting: when do you use a vector database vs. a keyword index? How do you design an immutable event log for consent state? What does "low-temperature generation" actually buy you in a compliance context?

I'll write about these as they come up.

Why write at all?

I find that writing forces precision. You can hold a fuzzy understanding of a system design in your head for a long time — writing it down exposes the gaps. So this blog is partly for anyone who finds it useful, and partly for me.

If you want to get in touch: hi@markz.io or LinkedIn.