(Senior) Backend Engineer

At Cobalt Streamworks , we believe small merchants are the heartbeat of our communities. By joining the Payments BR Tribe , you'll help shape solutions that directly solve merchants' everyday challenges and redefine how financial products empower entrepreneurship in Brazil. The tribe is deeply focused on the Brazilian market — understanding the real needs and behaviours of our merchants and building products that truly fit their world. You'll be part of a global, autonomous, cross-functional team of driven, purpose-led people who take ownership, embrace challenges, and care deeply about helping businesses succeed. As a (Senior) Backend Engineer , you'll be the technical anchor of a small, high-impact squad — bringing clarity to complex integration logic, setting the architectural direction, and helping a growing engineer reach their potential. This is a role for someone who finds satisfaction in making hard systems reliable, loves writing clean Go code, and isn't afraid to navigate the complexity that comes with building at scale in a fast-growing market. What you'll do Own the architecture: Design and author RFCs that shape how the domain evolves, driving clean, scalable solutions across our integration layer with internal Cobalt Streamworks services and third-party services as well. Write and review high-quality code: Take full ownership of backend delivery — from writing production-grade code to leading rigorous peer reviews that keep the codebase healthy and maintainable Drive technical standards: Establish clear documentation, testing practices, and CI/CD improvements that reduce technical debt and make the squad more autonomous over time Mentor and grow the team: Pair-program with and actively develop other engineers on the squad, acting as the technical reference point and fostering a culture of ownership and engineering excellence Collaborate broadly: Partner closely with the Engineering Manager, Product Manager, and cross-functional stakeholders to translate business needs into clear technical roadmaps and scalable solutions What makes you a great fit Solid backend development skills, with experience in Go, or strong experience in functional backend programming languages with a genuine drive to master Go quickly Strong expertise in code design, automated testing, CI/CD, performance optimisation, and building resilient, well-architected systems A track record of leading technical projects end to end — from writing design documents to shipping production improvements that hold up at scale Hands-on experience with AWS Cloud services and strong SQL optimisation skills with relational databases Have advanced English proficiency, with the ability to present and discuss technical topics clearly across teams and with non-technical stakeholders Experience contributing to technical strategy beyond the immediate squad Why you should join Cobalt Streamworks 🌍 Global Experience : Collaborate with a diverse team of 3,000+ people from over 90 countries, and join our global off-sites and hackathons. 🤝 Collaborative Culture: Join a team that values diversity, innovation, and teamwork, where your ideas and contributions truly matter. 📈 Career Growth : Be part of a global team working on large-scale fintech products used by millions of businesses. 💙 Great Benefits : Health plans, meal vouchers (VR), Zenklub, Wellhub, life insurance, childcare allowance, and more. 📚 Learning & Development : Access an annual budget of R$ 10,000 for education, certifications, and conferences. 🌴 Time Off : Enjoy 30 additional days off through our Break4Me program after 3 years at Cobalt Streamworks. 💸 Grow with Us: Participate in our virtual stock program and benefit from Cobalt Streamworks’s success with company shares. Learn More About Cobalt Streamworks 🇧🇷 Office tour at São Paulo 💡 Ask me anything: Engineering at Cobalt Streamworks 🚀 Cobalt Streamworks’s Innovation Hackathon 🤝 Get to know our hiring process Ready to Join us? Apply now and help us shape the future of financial solutions for small businesses Job Application Tip We recognise that candidates feel they need to meet 100% of the job criteria in order to apply for a job. Please note that this is only a guide. If you don’t tick every box, it’s ok too because it means you have room to learn and develop your career at Cobalt Streamworks.