Rules become interfaces.
Interfaces become trust.
That’s the work.

Ten years in tech, across four countries and two markets. Most of it spent where trust has to be built into the screen: payments, marketplaces, creator platforms, and now healthcare.

Guilherme Santiago at a desk, marking up a printed layout next to an open laptop, in a blue duotone treatment.

What I do

I’ve spent nearly ten years designing the moment someone decides to trust a screen with something that matters — money, an investment, a trade they’re learning. Same craving every time: watch the decision I made show up in how a person actually behaves.

Most recently, I built a payments platform from zero as its first and only designer: no PM, no team to inherit a playbook from, no system that existed before me. I’m starting a new chapter now, on the team behind Prontuário at Afya — a different kind of user to learn before I try to change anything for them.

20+ products shipped in under a year

41 PRs in ~5 weeks

42 growth Experiments in two years

  • Afya

    Senior Product Designer

    2026 – Present

  • PagAmerican

    Senior Product Designer

    2025 – 2026

  • Inter&Co

    Third-party US · as Product Designer

    2024 – 2025

  • Mercado Livre

    Senior UX Designer

    2022 – 2024

  • Hotmart

    Mid Product Designer

    2017 – 2022

Selected work