Senior Full Stack Engineer (Checkout) in Tremblay-en-France, Île-de-France at Jobgether

This position is posted by Jobgether on behalf of a partner company. We are currently looking for a Senior Full Stack Engineer (Checkout) in France.

This is an exciting opportunity to join a fast-moving engineering environment focused on building scalable checkout and transaction infrastructure within the Web3 ecosystem. In this backend-heavy full-stack role, you will own critical funding and payment flows end to end, from frontend interfaces to backend integrations and lifecycle management systems. You will work on complex integrations involving payment providers, exchanges, and blockchain-based services while collaborating across multiple technical teams. The role requires strong architectural thinking, product awareness, and the ability to independently navigate distributed systems and evolving priorities. You’ll contribute to building resilient, user-friendly transaction experiences in a highly collaborative and remote-first environment. This position is ideal for engineers passionate about scalable systems, modern TypeScript stacks, and the future of crypto-powered financial infrastructure.

• Design, build, and maintain backend systems powering checkout and transaction flows, including sessions, quotes, provider integrations, status handling, and recovery processes.
• Develop scalable integration patterns for external providers such as payment services, exchanges, and on-ramp platforms while ensuring a consistent user experience.
• Define and maintain reliable backend contracts between frontend interfaces, provider systems, and execution infrastructure.
• Build and improve long-running transaction workflows with strong attention to observability, resilience, failure handling, and recovery mechanisms.
• Contribute to frontend development when required, particularly around UI states tightly coupled with backend workflows and APIs.
• Collaborate with cross-functional engineering teams to ensure architectural consistency and seamless integration across products and services.
• Participate in technical discovery, system design discussions, and roadmap planning for future checkout and payment-related capabilities.
• Continuously improve performance, maintainability, and scalability across distributed services and user-facing components.

• Strong professional experience in backend engineering using Node.js and TypeScript, combined with full-stack capabilities using React and TypeScript.
• Proven expertise integrating external APIs and managing provider-specific edge cases in complex asynchronous systems.
• Solid understanding of distributed systems, observability, recovery flows, and resilient backend architecture.
• Working knowledge of Web3 technologies, including blockchain transactions, wallets, DEX aggregators, and related ecosystem concepts.
• Experience with modern development environments and infrastructure tools such as Docker, Kubernetes, AWS, MongoDB, Redis, and GitOps workflows.
• Familiarity with frontend libraries and frameworks such as React, viem, wagmi, or similar technologies is a plus.
• Strong communication and collaboration skills, with the ability to work independently across multiple teams and codebases.
• Comfortable operating in fast-paced, high-growth, and highly iterative product environments.
• Passion for crypto, fintech, payments, or decentralized technologies is highly valued.
• Eligibility to work remotely within the EMEA region is required.

• Fully remote work environment with flexible working hours and location flexibility across the EMEA region.
• 30 days of paid time off annually.
• Equity participation from day one.
• Annual international team offsites in unique global destinations.
• Choice of work equipment and home office flexibility.
• One-time remote work budget to support office setup or coworking expenses.
• Annual professional development budget for continued learning and skill growth.
• Collaborative, transparent, and inclusive company culture focused on ownership, growth, and innovation.
• Opportunity to work on cutting-edge Web3 infrastructure with high technical impact and product ownership.