César Noreña

Open to a few projects

I help product teams put AI into production — and build the mobile and backend systems it runs on.

Ten years in consumer products, most of it in fintech, where a bug costs someone real money. I'm a software engineer on Nubank's AI Core team, and I take on a small number of outside projects alongside it.

What I do

  • AI & LLM integration

    Getting language models from a convincing demo to something you can put in front of customers — evaluation, guardrails, cost, latency, and the unglamorous plumbing that decides whether it holds up.

  • Mobile apps

    Flutter and Kotlin, greenfield or rescue. Multi-package architecture and a codebase your team can still move quickly a year from now.

  • Backend & architecture

    Event-driven services on AWS. Distributed systems that fail predictably, with the monitoring and alerting to prove it.

  • Advisory & architecture review

    Architecture review, mentoring, and engineering practice for teams that need senior judgment without adding a senior headcount.

On staff at

Founding engineer at QINV, where I built a B2C investment product end to end. Before that, launching Nubank's first product in Mexico, and rebuilding the app and the services behind iFood's multi-balance benefits card.

How I work

I trained as an interaction designer before I wrote production code, so I tend to argue about the product, not only the implementation. Expect questions about who this is for and what happens when it breaks.

Small scope, shipped, then the next one. I'd rather hand back something narrow that works than something broad that needs me to keep explaining it.

Get in touch

Tell me what you're building and where it's stuck.

Message me on LinkedIn