Guillermo Casanova
Senior software engineer with 5+ years across startups, fintech, e-commerce, and AI-native products. I build agent infrastructure, fast web and mobile interfaces, and observable, cost-aware systems.
Four things I keep measurable.
Fast initial load
Image budgets, lean bundles, prefetching, and removing work before users feel it.
Predictable user flows
Flows that stay predictable under real data, with clear states and accessible feedback.
Developer experience
Typed APIs, reusable primitives, fast local feedback, and CI that helps teams move without guessing.
Observable quality
Tests, evals, observability, and production metrics so regressions are visible early.
Product systems that ship and stay shipped.
AI-native product systems
Agent workflows, tool calling, structured outputs, eval harnesses, and observability loops that make model behavior measurable before it reaches production.
Product infrastructure
Frontend, mobile, backend-for-frontend, caching, search, and deployment pipelines when the product needs speed without splitting ownership.
Measured delivery
Small, verifiable increments: profile the bottleneck, reduce the moving parts, automate the check, and keep the business metric visible.
Tools I reach for first.
AI
Product
Mobile
Platform
Quality
Observability
Four working rules I don't break.
- Own the outcome across the product surface, not only the ticket boundary.
- Treat performance, cost, and quality as numbers to observe, not opinions to debate.
- Automate the repetitive, frictionless workflows let the team spend its judgment on outcomes, not toil.
- Use AI and automation for repeatable engineering work, then verify the result with tests and production signals.