João Marins
Some things about me:
- Software engineer, entrepreneur, angel investor and open source maintainer
- Live in Brazil
- Studied Computer Science and Physics at Universidade de São Paulo
- Founded Confy and Angora Labs, and co-founded bem.te.vi
- Mostly work with Node.js, React, React Native, TypeScript, GraphQL, Relay, MongoDB, AWS and K8s
- Write at joaomarins.substack.com
- Also known as Gracinha
Experience
- Feb 2024 — Present — Software Engineer at Sunrun, San Francisco, California, United States
About this experience
- A US-based clean energy company that designs and installs residential solar and battery systems, making home energy more affordable and sustainable.
- React, TypeScript, Node.js, Python, AWS, DynamoDB, GraphQL
- Sep 2023 — Feb 2024 — Technical Leader at Woovi, Brazil
About this experience
- A Brazilian fintech platform that enables businesses to accept instant payments through Pix, automating invoices, subscriptions, and checkout experiences for merchants of all sizes.
- React, TypeScript, Node.js, Relay, GraphQL, AWS, K8s, MongoDB
- Apr 2022 — Sep 2023 — Co-Founder & CTO at bem.te.vi, Brazil
About this experience
- A Brazilian insurtech focused on simplifying property insurance through technology, offering fast, transparent, and fully digital coverage for homes and rentals.
- React, TypeScript, Node.js, Relay, GraphQL, AWS, MongoDB
- Apr 2021 — Apr 2022 — Software Engineer at Curebase, San Francisco, California, United States
About this experience
- A US-based health-tech company that enables decentralized clinical trials through a virtual-first platform connecting patients, physicians, and sponsors to accelerate medical research.
- React, TypeScript, Node.js, Apollo, GraphQL, AWS, Postgres
- Oct 2020 — Mar 2021 — Technical Leader at Sallve, Brazil
About this experience
- A Brazilian beauty-tech company that develops skincare products co-created with its community, combining dermatological science, sustainability, and digital innovation.
- TypeScript, Node.js, AWS, MongoDB
- Feb 2020 — Oct 2020 — Founder & CTO at Angora Labs, Florianópolis, Santa Catarina, Brazil
About this experience
- A Brazilian product analytics and data pipeline platform that captures user events via SDKs and routes them to warehouses and dashboards for real-time insights.
- React, TypeScript, Node.js, Relay, GraphQL, AWS, MongoDB
- Aug 2019 — Feb 2020 — Founder & CTO at Confy, Florianópolis, Santa Catarina, Brazil
About this experience
- A Brazilian events platform that lets communities create, discover, and manage meetups—handling event pages, RSVPs, scheduling, and attendee engagement.
- React, TypeScript, Node.js, Relay, GraphQL, AWS, MongoDB
- Jul 2018 — Apr 2019 — Software Engineer at Feedback House, São Paulo, Brazil
About this experience
- A Brazilian HR-tech platform that helps companies foster a culture of continuous feedback, performance reviews, and employee engagement through data-driven insights.
- React, TypeScript, Node.js, Relay, GraphQL, AWS, K8s, MongoDB
- Jul 2017 — Apr 2019 — Software Engineer & Technical Leader at Entria, São Paulo, Brazil
About this experience
- A Brazilian software consultancy that builds and scales web applications using modern technologies, where I later led technical teams and architectural decisions for client projects.
- React, TypeScript, Node.js, Relay, GraphQL, AWS, K8s, MongoDB
Education
- 2013 — 2017 — Bachelor's degree, Computer Science, Universidade de São Paulo, São Paulo, Brazil
- 2011 — 2012 — Bachelor's degree, Physics, Universidade de São Paulo, São Paulo, Brazil
Talks & Presentations
- Beyond the Basics: Leveraging MongoDB for Fintech Disruption (2024)
About this
- Exploring MongoDB database solutions and best practices for financial technology applications.
- Relay Local State Management: Replacing Redux (2019)
About this
- How to use Relay for local state management as an alternative to Redux in React applications.
- Serverless Deployment of React Apps on AWS (2019)
About this
- Guide to deploying React applications on AWS using serverless architecture and best practices.
- The Golden Stack (2019)
About this
- React Conf Brazil 2019 presentation on building modern web applications using React, Relay, and GraphQL.
- How to improve CI/CD for any Node.js application? (2019)
About this
- A comprehensive guide on improving continuous integration and deployment processes for Node.js applications.
- React Hooks (2019)
About this
- Deep dive into React Hooks, exploring how to use them effectively in modern React applications.
- CI/CD for React Native (2018)
About this
- Implementing continuous integration and continuous deployment pipelines for React Native mobile applications.
- RTL Everywhere (2018)
About this
- React Testing Library best practices for testing React applications and improving test reliability.
- GraphQL Security (2018)
About this
- Best practices and strategies for securing GraphQL APIs and preventing common security vulnerabilities.
- Building a Cryptocurrency App with React Native (2018)
About this
- Learn how to build a cryptocurrency mobile application using React Native and modern development practices.
- Git: From Commit to Merge (2018)
About this
- Workshop covering Git fundamentals, from basic commits to advanced merging strategies and workflows.
Links
- GitHub: github.com/jgcmarins
- LinkedIn: linkedin.com/in/joao-marins
- X (Twitter): x.com/jgcmarins
- Instagram: instagram.com/joaogracinha
- Strava: strava.com/athletes/jgcmarins
- Substack: joaomarins.substack.com
- Medium: medium.com/@jgcmarins
- SlideShare: slideshare.net/JoaoMarins1
- Dev.to: dev.to/jgcmarins
- Bluesky: bsky.app/profile/jgcmarins.dev
- Mastodon: mas.to/@jgcmarins
- Keybase: keybase.io/jgcmarins
Contact
Always interested in new opportunities, collaborations, and conversations about technology, entrepreneurship, and innovation.
© 2026 João Marins. All rights reserved.