Elaine
Mattos
Senior software engineer with 8+ years across product and fintech, building the interface, the services and the payments behind it.
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About
Good engineering is mostly good judgment: what to build, what to leave out, and what to make boring on purpose.
I work across the whole stack: React and Next.js on the front, Go, Ruby on Rails, Node.js and Kotlin behind it. That range lets me follow a problem to wherever it really lives, whether that's a screen, a queue or a payment flow.
I've built for creators at Teachable, for high-volume Pix and boleto payments at Cora, and led a small team shipping client work. I care about small decisions that compound: a clear name, a well-shaped API, a system that's easy to observe when it misbehaves. Before software, I spent a season in Iceland leading environmental projects with international volunteer groups, which taught me to work well with people from anywhere.
Interfaces
- JavaScript & TypeScript
- React, Next.js, Redux
- Tailwind, shadcn/ui, Sass
- Angular, React Native, Ionic
Systems
- Go & Ruby on Rails
- Node.js & NestJS
- Kotlin & Spring Boot
- Kafka, PostgreSQL, MySQL
Practice
- Vitest, Jest, Playwright
- Datadog & New Relic
- Docker & GitHub Actions
- Technical leadership & mentoring
Education — B.Sc. in Computer Science, Universidade Paulista (UNIP), 2021
Work
Teachable
Aug 2023 – PresentSenior Software Engineer
- Architected and built integrations as microservices in Go and Ruby on Rails, making cross-system data flows more reliable.
- Delivered React product features used by thousands of platform customers.
- Led front-end and back-end work on a payments system modernization.
- Built AI-powered features for content creators, and contributed to the platform’s public API.
- Strengthened account security by improving authentication.
- Built internal tooling for content moderation and policy enforcement, cutting manual review.
- Standardized dev environments with Docker; established test coverage with Vitest, Jest, Playwright and Postman.
- Added observability with New Relic and Datadog to detect and respond to incidents faster.
Cora
May 2022 – Jul 2023Software Engineer
- Built back-end financial services in Kotlin and Spring Boot for Pix instant payments and boleto transactions.
- Applied hexagonal architecture to decouple business logic from infrastructure.
- Implemented Kafka messaging for reliable, asynchronous processing of transactions.
- Set up CI/CD with GitHub Actions and standardized deployment with Docker.
- Delivered highly available systems for a high-volume fintech product.
Level Um
Apr 2021 – Apr 2022Software Engineer & Tech Lead
- Led and mentored a development team across multiple concurrent client projects.
- Built and published a fitness mobile app (Ionic/React) to the App Store and Google Play.
- Delivered e-commerce and construction platforms with Rails, Node.js and NestJS.
- Implemented vulnerability scanning tooling for a security-focused client.
- Chose data storage (PostgreSQL, MySQL, Firebase) to fit each project.
Vultus Cybersecurity
Aug 2020 – Apr 2021Front-end Developer
- Built and maintained web applications with Angular 9 and Node.js.
- Supported vulnerability report analysis, with working exposure to Java and Scala.
- Worked with UI and design teams on high-impact visual solutions.
- Maintained legacy systems to keep the platform stable.
Proativa Solutions
Aug 2019 – Apr 2020Front-end Developer
- Built the front-end of the Quinto app with React, Redux and Firebase.
- Maintained and extended a legacy PHP backoffice with heavy MySQL work.
- Integrated the legacy backoffice with the new application, improving usability and performance.
Codeminer42
Mar – May 2019Web Developer Intern · Sorocaba
- Front-end development with vanilla JavaScript, HTML, CSS and Sass, and React with Jest.
- First hands-on work with Ruby and Ruby on Rails, the stack I still use today.
Woopi
Feb 2018 – Feb 2019Software Tester Intern · Sorocaba
- Researched and wrote test cases, and documented tests and results.
- Analyzed quality metrics and managed bugs through to resolution.
- Studied and built automated tests, where my interest in reliable software started.
Worldwide Friends Iceland
Sep – Dec 2017Project Leader (Volunteer) · Iceland
- Led environmental and community projects in three parts of Iceland: sustainable living near Reykjavík, health and environment in Hveragerði, and photography and journalism in Eskifjörður.
- Prepared, organized, ran and evaluated projects with international volunteer groups, under the supervision of the organization’s project manager.
- Handled group management and awareness campaigns; work from the photography and journalism project was published in UNA Magazine.
Contact
If this is how you like to work, let’s talk.
elainecmmattos@gmail.comI read every message and reply in my own time. New teams, thoughtful products and good questions are all welcome.