Hi, I'mÁngel NereiraÁngel NereiraFull Stack Software Engineer
Engineer specialized in FinTech, GovTech, and SaaS platforms. I build modern applications that work on any device, ensuring security and scalability.
Solutions that Scale
High-level software engineering for products that need performance, security and availability.
About Me
Full Stack Software Engineer specialized in FinTech and GovTech. I design and build scalable SaaS systems that process thousands of daily transactions, with a relentless focus on client ROI.
The Origin
My engineering journey began by facing the most critical problem in business digitalization in emerging markets: systems that fail exactly when they are needed most. Building Sago One from scratch forced me to master offline-first architectures, government fiscal compliance, and bank-grade security protocols — not as academic exercises, but as business imperatives with real financial consequences. Every architectural decision I make starts with a central question: what is the direct impact on the client's operational balance sheet?
Production Ecosystem
Sago One processes over 10,000 DGI-certified electronic invoices, operates a touch POS, manages legal payroll, and maintains 99.9% uptime with a PWA architecture that works without internet. Plenty Market integrates a logistics Partner Program with tax-free zones and real-time inventory sync. Both are technological assets protecting the financial interests of real businesses, every day, with latencies under 200ms.
Engineering Pillars
Principles guiding every architectural decision and every line of code
Architecture First
The tech stack is a consequence of the architecture, not the other way around. Every project starts with an analysis of non-functional requirements: scalability, fault tolerance, security. This prevents technical debt that erodes client ROI.
Non-Negotiable Security
In FinTech systems, security is not a layer added at the end. AES-256, robust authentication, and strict data validation are part of the initial design. Regulatory compliance is not optional: it is the product.
Software as an Asset
Strict TypeScript, clear documentation, and modular architectures are the difference between a system that scales for years and one that accumulates technical debt. The software I deliver is a capital asset, not an operating expense.
Value in Business Terms
CTOs and CFOs don't invest in lines of code; they invest in predictable financial outcomes. I translate every technical decision — latency, uptime, scalability — into its direct impact on revenue, operating costs, and business risk.
"Clean code, scalable solutions, clear documentation"
Frequently Asked Questions
Answers to the most common questions about my services and methodology.
Need high-level development?
Let's build systems that scale. Available for FinTech, E-commerce and SaaS projects.
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