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Guilherme MartinsPT Português, ler em português

About

I'm a software engineer focused on product engineering and software architecture. I build full-stack products that hold up in production, and I use coding agents across the development cycle in a spec-driven process with tests, quality gates and human review.

Architecture is where I am going deepest. On an AI-first credit platform I work on a modular, hexagonal core with replayable event ingestion, and I record decisions as ADRs. I am also studying for a postgraduate specialization in distributed software architecture.

I work agentically: coding agents take part in every step, from spec to review, inside a spec-driven process I open-sourced as sdd-agentic-flow. AI multiplies the work and judgment stays with people, so nothing ships that I have not reviewed and can explain.

I have worked with teams in Brazil and the UK in fintech, SaaS, AI-driven products, cybersecurity, healthcare and creative software. Frontend architecture and design systems remain among my strongest areas, and architecture and technical direction are where I am focusing next.

Much of this work is under confidentiality terms. The Cases page shows what is public.

Experience

  1. 2026 - present

    Belo Horizonte, Brazil

    AI-first fintech

    Senior Software Engineer

    Credit and banking platform designed AI-first. The company is confidential; the case study describes the work in general terms.

    • Work on the core platform: a modular monolith with hexagonal architecture and replayable event ingestion.
    • Integrate the core with the conversational AI layers, built by colleagues, behind guardrails that keep sensitive data away from models.
    • Built the partner landing page, with SEO and Core Web Vitals treated as product scope.

    Read the case study (AI-first fintech)

  2. 2025 - 2026

    Belo Horizonte, Brazil

    gmartins.dev

    Software Engineer

    Independent software engineering for clients in several industries.

    • Maintained and evolved a medical workforce management system: shift scheduling, operational workflows and healthcare payments.
    • Designed and delivered the menu management feature of a data platform for food-service businesses, including statistical analysis.
    • Built marketing and acquisition websites with semantic HTML, performance work and PostHog analytics.

  3. Mar 2025 - Jun 2025

    Cardiff, UK

    Nisien.ai

    Software Engineer

    AI-driven cybersecurity startup focused on online threat analysis.

    • Built the main customer-facing application of the AI product from its first version.
    • Designed and implemented the company design system: reusable components and frontend architecture.
    • Worked with the tech lead on architecture, infrastructure alignment and frontend security.

    See the product (Nisien.ai)

  4. Oct 2024 - Feb 2025

    Cardiff, UK

    Backbase

    Software Engineer

    Fintech that builds an engagement banking platform for financial institutions.

    • Implemented customer-journey features for onboarding, servicing and lending with cross-functional teams.
    • Built a proof-of-concept AI chat assistant for staff handling customer requests. It won the internal hackathon.

    See the product (Backbase)

  5. Jan 2024 - Aug 2024

    London, UK

    Vochlea

    Software Engineer

    AI-powered software for music production.

    • Built responsive React, Next.js and TypeScript interfaces backed by a headless CMS and REST APIs.
    • Maintained Node.js and Express APIs with OAuth2 authentication and authorization.
    • Worked with marketing, design and product to turn requirements into product experiences.

    See the product (Vochlea)

  6. Apr 2023 - Oct 2023

    Moreton-in-Marsh, UK

    Loop

    Software Engineer

    Property management CRM used by UK estate agencies.

    • Maintained and extended CRM features as client workflows changed.
    • Designed user-centred workflows with the product and sales teams.

    See the product (Loop)

  7. Oct 2022 - Mar 2023

    Madrid, Spain

    ChatWith.io

    Frontend Developer

    Contract work on a SaaS platform that helps businesses run marketing, sales and customer relationships through WhatsApp.

    • Built and maintained customer-facing features of the web application in Vue.js and JavaScript.
    • Investigated and fixed frontend issues that affected the platform's users day to day.
    • Implemented responsive interfaces from product and design requirements with Sass, Bootstrap and Figma.

    See the product (ChatWith.io)

  8. Sep 2021 - Oct 2022

    Belo Horizonte, Brazil

    Freelance

    Full-Stack Developer

    Freelance and independent web projects.

    • Delivered web applications end to end: planning, design, implementation, deployment and client communication.

Education

  • Postgraduate specialization in Distributed Software Architecture

    PUC Minas, Sep 2026 - Mar 2028, in progress

Tools I use

AI-assisted engineering
Claude Code, Codex, Cursor, GitHub Copilot, MCP
Languages
TypeScript, JavaScript, Go, HTML, CSS, SQL
Frontend
React, Next.js, Angular, Vue.js, React Native, Tailwind CSS, Storybook
Backend and data
Node.js, NestJS, Express, REST, GraphQL, PostgreSQL, MongoDB
Delivery and quality
AWS, Azure, Google Cloud, Vercel, Docker, GitHub Actions, Playwright, Jest

Resume

The resume has the same history in a printable format.