Payments & Crypto R&D Engineer

Ming-Li Liu

25+ years building the hard parts of payments — from EMV smart cards and NFC to DeFi rails, proximity payments, and agentic commerce.

25+ Years in FinTech & Payments
MLL11
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About

I am a payments and crypto R&D engineer with 25+ years spent on the parts of the payment stack most people never see — the standards, the silicon, the cryptography, and the settlement rails underneath the apps.

My fintech career started at Visa International, developing reference implementations of EMV — turning specifications into working prototypes. From there I built contactless / NFC payment and acceptance products at ViVOtech; as CTO of Zenius Solutions, delivered integration services and white-label payment solutions; and, as Director of Software Engineering at SimplyTapp, led the engineering behind host card emulation (HCE) — cloud-based NFC payments.

Most recently I built PayFac risk and onboarding infrastructure at Poynt by GoDaddy. Today I run MysDeFi LLC, building decentralized-finance and payment prototypes at the intersection of that foundation and what is newly possible — crypto micropayment rails, BLE/UWB proximity payments, and AI-driven agentic commerce.

What ties it all together: I like the ambiguous, technically risky problems — the ones where nobody is sure yet whether the idea will actually work — and I like being the person who finds out. If you would like to work together, that happens through my studio, MysDeFi LLC.

Expertise

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Payments & FinTech
Standards-level fluency across card, mobile, and crypto rails — from acquiring and risk logic to DeFi settlement.
EMV GlobalPlatform ISO 7816 Contactless / NFC / ISO 14443 ISO 8583 Mobile / P2P Payments Stellar / DeFi / Payments
Full-Stack Engineering
Backend to native mobile in one set of hands — built to move a prototype fast without cross-team handoffs.
Python / FastAPI / FastMCP React / Node.js / TypeScript Java / Spring Boot iOS (Swift) Android Flutter
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Cloud & Data Infrastructure
Production-grade deployment and data pipelines for prototypes that need to hold up under real usage.
GCP / Firebase AWS Docker LiteLLM MySQL / MongoDB CI/CD
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Hardware & Security
Deep embedded and cryptographic expertise — where most fintech PoCs actually run into trouble.
Cryptography / HSM Tokenization Smart Cards / JavaCard Embedded Firmware
Building something in payments or fintech?
I take on proof-of-concept engagements through MysDeFi LLC — turning technically risky ideas into decision-ready prototypes, discovery through demo, typically in 2–6 weeks.
Visit MysDeFi