Alfonso Guillen

I’m a Senior full-stack engineer backend-focused and a Technical Lead with 8+ years designing, building, and scaling backend systems for fintech and high-traffic platforms. I’ve owned architectural decisions, mentored engineers, and delivered reliable, secure systems handling real financial transactions—stepping into the Tech Lead role formally after years acting as the de-facto leader.

At n1co, I led a cross-functional team across frontend, backend, and QA—setting technical direction, unblocking daily, and maintaining a high delivery bar in a fast-moving fintech environment. I partnered with Product to co-define the roadmap, challenge requirements, and translate complex business needs into clear, executable technical plans.

I now extend that foundation into AI: building agentic prototypes, wiring LLMs to live financial data, and shipping working experiments in 2–3 day cycles. I’m drawn to teams that treat AI as a serious engineering discipline, and I believe the best way to learn a new tool is to build something real with it fast.

My work spans microservices, event-driven architectures, secure API design, and scalable data pipelines. From an AI-powered financial assistant and digital wallet reliability improvements to automated PR review agents and OCR structured extraction pipelines, I focus on practical outcomes, security, and dependable systems.