Senior Product Engineer, Treasury (Elixir)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Product Engineer, Treasury (Elixir) based in the United States. Join an innovative engineering team building an AI-powered finance platform that transforms how enterprises manage payments, treasury, and financial operations. As a Senior Product Engineer, you will design and scale the core services behind a treasury platform handling billions in transaction volume. Your work will help enable next-generation financial workflows, including AI agents that initiate corporate expenses, manage travel, and use payment cards. Working closely with founders and a small, senior team across engineering, product, treasury, and data/AI, you will shape product direction and technical architecture. This hands-on role combines deep Elixir expertise with end-to-end product ownership, from defining requirements and building interfaces to operating reliable production systems. The position is fully remote for US-based candidates working Eastern Time hours, with significant autonomy and opportunities to influence the future of financial technology.

As a Senior Product Engineer, you will take ownership of critical treasury product capabilities, building reliable backend services and complete user-facing features. You will contribute to technical strategy, establish strong engineering practices, and help deliver resilient systems that support increasingly sophisticated financial workflows. Design, build, deploy, and operate Elixir and Phoenix services, including APIs, data pipelines, and asynchronous processing systems. Own product features throughout the entire software development lifecycle, from problem discovery and requirements definition to backend implementation, frontend delivery, and production operations. Develop and scale core treasury services that support high-volume financial transactions and emerging AI-driven spending workflows. Build and improve infrastructure that enables AI agents to initiate corporate expenses and travel, as well as create and use payment cards. Prioritize reliability across critical Tier 0 and Tier 1 systems through robust observability, monitoring, and operational practices. Collaborate directly with company founders and senior colleagues across treasury, product, engineering, and data/AI to shape product direction and technical decisions. Use AI-assisted development tools, particularly Claude Code, to improve engineering productivity and support high-quality implementation. Help establish and refine architectural standards, engineering workflows, development practices, and code review processes. Contribute to a collaborative engineering culture focused on end-to-end ownership, maintainability, and dependable production systems. Requirements: The ideal candidate is an experienced product-minded engineer with strong production experience in Elixir and Phoenix, a solid understanding of distributed systems, and the ability to deliver complete features independently. You should combine technical depth with clear communication, sound product judgment, and practical experience using AI-assisted development tools. Be based in the United States and able to work Eastern Time hours in close collaboration with the treasury team. Have at least 5 years of professional software engineering experience. Demonstrate strong hands-on experience developing and operating production applications with Elixir and Phoenix. Be comfortable owning features end-to-end, from product framing and requirements through backend services, frontend implementation, and production support. Have a solid understanding of distributed systems, concurrency, and asynchronous processing. Possess strong PostgreSQL skills and practical experience with cloud infrastructure, Kubernetes, and CI/CD pipelines. Demonstrate fluent, day-to-day use of AI coding tools, particularly Claude Code, in real software development workflows. Communicate clearly with both technical and non-technical stakeholders. Have fluent English communication skills. Nice-to-have qualifications: Experience with Python or other backend programming languages. Background in payments, treasury, fintech, or related financial technology domains. Familiarity with event-driven architectures, message queues, and workflow orchestration. Exposure to AI- or machine learning-powered products. Benefits: Competitive compensation: Salary package designed to reflect experience and expertise. Meaningful equity: Opportunity to participate in the company's growth and success. AI tooling budget: Extensive resources for AI-assisted development and engineering productivity. Generous paid time off: Support for rest, personal commitments, and work-life balance. Remote-first flexibility: Fully remote work with a flexible schedule, aligned with Eastern Time collaboration. Health and wellness: Comprehensive health coverage and wellness benefits. Autonomy and ownership: Direct influence over product direction, architecture, and engineering decisions. Innovative technical environment: Opportunity to build advanced payment and treasury infrastructure, including AI-driven financial workflows. Inclusive culture: A commitment to diversity of thought, culture, and background, with equal employment opportunities.