Full Stack Engineer (Elixir Backend Focus)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Full Stack Engineer (Elixir Backend Focus) based in Brazil. Join an international, AI-first team building the infrastructure that connects loyalty programs and transforms reward points into a practical payment method. As a Full Stack Engineer with a strong backend focus, you will take ownership of core services, partner-facing APIs, and dashboards that support reliable loyalty transactions. You will work extensively with Elixir, Phoenix, PostgreSQL, React, and TypeScript to deliver scalable, secure, and well-documented solutions. From architecture and development to deployment, monitoring, and continuous improvement, you will contribute throughout the entire software lifecycle. AI-powered coding tools will be central to your daily workflow, helping you accelerate delivery while maintaining high standards of code quality and system correctness. Collaborating closely with product and infrastructure teams, you will help strengthen a platform where reliability, clear technical reasoning, and continuous learning are essential. Accountabilities: You will own backend services and full-stack features that support partner integrations and the platform's core transaction workflows. Your responsibilities will include: - Design, build, and operate Elixir services using Phoenix, Ecto, and OTP, including APIs, workers, and background jobs. - Develop and evolve partner-facing REST APIs, including API versioning, outbound webhooks, and reliable delivery mechanisms. - Build and maintain money-adjacent systems where accuracy is essential, including double-entry ledgers, loyalty point balances, settlement, and reconciliation. - Own frontend features from end to end using React and TypeScript, covering administrative interfaces, partner dashboards, and their supporting APIs. - Use AI coding agents such as Claude Code regularly to accelerate development, while carefully reviewing generated code for correctness, security, and maintainability.

- Conduct meaningful code reviews and provide an additional layer of scrutiny for system design, transaction integrity, and overall platform reliability. - Document technical decisions through clear pull request descriptions, architecture notes, and documentation updates delivered alongside code changes. - Collaborate with product and infrastructure teams on AWS deployment, monitoring, security, and ongoing platform improvements. Requirements: You should bring substantial software engineering experience, deep production-level Elixir expertise, and the ability to take ownership of both backend systems and frontend features. The role requires strong technical judgment, an AI-first mindset, and a commitment to building reliable software. Key qualifications include: - At least 6 years of professional software engineering experience, including 4 or more years focused on backend development. - At least 3 years of production experience with Elixir, Phoenix, Ecto, and OTP, including shipping, operating, and maintaining production systems. - Daily use of AI coding tools such as Claude Code, Cursor, or equivalent, with the ability to evaluate and validate their output. - Strong PostgreSQL expertise, including practical SQL, transaction semantics, and performance optimization. - Solid experience designing REST APIs and implementing background job processing with retries, using Oban or an equivalent solution. - Demonstrated experience in loyalty platforms, travel technology, payments, or FinTech. - At least 2 years of React and TypeScript experience, with the ability to independently deliver complete frontend features, including components, state management, forms, validation, and error handling. - Working knowledge of AWS services such as ECS, RDS, and S3, along with Docker and CI/CD workflows using GitHub Actions.