Software Engineer & React Native & Full Stack

We are looking for a senior, product-minded software engineer to take ownership of major parts of the product across React Native, backend services, APIs, integrations, testing, and release.

You will own features end-to-end across the React Native application, backend services, APIs, and integrations.

You will work closely with the founders, product, and design teams to move ideas from concept to production. You should be comfortable making pragmatic technical decisions, working without perfectly defined specifications, and owning features from beginning to end.

This is an opportunity to join a small team at an early stage and have a meaningful influence on the product, technical architecture, engineering standards, and company culture., * Own and ship product features end-to-end across the React Native application, backend services, APIs, and integrations.

• Build major parts of the mobile application across UI, state management, API integration, testing, and release.
• Build and maintain backend services using Node.js and TypeScript.
• Work directly with founders, product, and design to move quickly from concept to production.
• Debug complex issues across iOS, Android, backend services, and third-party integrations.
• Improve mobile performance, responsiveness, animations, and overall product quality.
• Make pragmatic architecture decisions as the product and engineering team grow.
• Help define engineering standards, tooling, development processes, and technical culture.
• Contribute to product quality and attention to detail across every customer touchpoint.
• Use AI development tools to improve engineering speed, quality, and output.

• At least five years of professional software engineering experience.
• Strong experience building and shipping production software.
• Proven experience developing and releasing production applications using React Native.
• Strong full-stack engineering ability across frontend, backend, APIs, and integrations.
• Experience with Node.js or similar backend technologies.
• Ability to own features from initial concept through development, testing, deployment, and release.
• Strong product judgment and attention to the customer experience.
• Comfortable working in a fast-moving, early-stage environment with limited structure.
• High level of ownership, initiative, and accountability.
• Willingness to work primarily from the Madrid office.

Nice to Have

• Experience building consumer-facing mobile products.
• Experience with Expo, native modules, mobile CI/CD, or App Store and Google Play releases.
• Experience with React and modern frontend development.
• Experience with AWS, Kubernetes, Terraform, or other infrastructure technologies.
• Experience in fintech, payments, digital banking, crypto, or Web3.
• Knowledge of EVM, Solidity, or blockchain infrastructure.
• Previous experience at an early-stage startup or as a founder.
• Experience helping establish engineering standards or culture within a growing team.

Our client is an early-stage fintech company building a global, non-custodial financial application designed to make moving and managing money simple and accessible. The product allows users to remain in control of their funds while spending and transferring money instantly across borders, without having to manage the complexity traditionally associated with crypto or self-custody. The company has a small, highly technical engineering team that ships quickly and cares deeply about product quality, usability, and customer experience.