Engineer - BackEnd

**About CloudWalk:** We are not just another fintech unicorn. We are a pack of dreamers, makers, and tech enthusiasts building the future of payments. With millions of happy customers and a hunger for innovation, we're now expanding our neural network \- literally and metaphorically. **About The Position** We are looking for a **Back\-End Developer** to help us automate and scale our entire chargeback process, across both acquiring and issuing operations. In this role, you will work on building and refactoring robust dispute flows, integrating with major card networks like Visa and Mastercard, and leveraging AI APIs to bring intelligence and automation to the core of our operation. * You’ll be responsible for connecting internal and external APIs, designing scalable architecture, and making our dispute handling smarter, faster, and more autonomous. **What You'll Be Doing** * Strong back\-end development experience (3\+ years), regardless of primary programming language. * Experience with RESTful APIs, background jobs, and service integrations. * Passion for refactoring legacy code and designing scalable solutions. * Understanding of payment networks (Visa/Mastercard) and/or chargeback operations is a strong plus. * Familiarity with AI tools or APIs (e.g., OpenAI, LangChain, ML models) is a nice\-to\-have. * Ownership mindset and willingness to build from scratch. * Willingness to occasionally work with Ruby, as part of the existing system is built on it. **What You Need To Succeed** * Strong Ruby/Rails experience (at least 3 years) * Experience with RESTful APIs, background jobs, and service integrations * Passion for refactoring legacy code and designing scalable solutions * Understanding of payment networks (Visa/Mastercard) and/or chargeback operations is a big plus * Familiarity with AI tools or APIs (e.g. OpenAI, Langchain, ML models) is a nice\-to\-have * Ownership mindset and a willingness to build from scratch **Join us at CloudWalk, where we’re not just engineering solutions; we’re building a smarter, AI\-driven future for payments—together.** By applying for this position, your data will be processed as per CloudWalk's Privacy Policy that you can read here in Portuguese and here in English. We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.