Senior Software Engineer

Senior Software Engineer at onhires. About the role Tuyo is building an accessible, non-custodial financial platform designed to make digital assets and cryptocurrency intuitive for users across the globe. As a foundational technical hire within this venture, you will play a central role in establishing core platform architecture and refining mobile product experiences directly alongside seasoned industry founders. This high-impact position demands strong technical leadership and cross-functional execution to turn ambitious fintech concepts into production-ready mobile software. You will help drive the technical vision for a modern web3-adjacent banking interface while shaping early engineering practices. Key facts Location: Madrid, Spain or Miami, FL (In-person, ~25% flexible remote days) Engagement: Full-time Compensation: High-tier base salary + 0.3% to 0.6% equity Team: Mobile Development What you'll do Take complete end-to-end accountability for client-side features, managing everything from UI design review and state architecture down to backend API integration and final production release on app stores. Write clean, maintainable, and high-performance TypeScript and JavaScript code to ensure mobile client reliability and longevity across mobile ecosystems. Partner directly with company co-founders and product designers to rapidly prototype, iterate, and refine user workflows for cryptocurrency management. Identify, diagnose, and resolve cross-platform performance bottlenecks across iOS, Android, and supporting backend systems to maintain high frame rates and low latency. Formulate foundational engineering protocols, software patterns, and testing strategies that set the benchmark for future technical hires. Establish continuous delivery workflows to streamline mobile deployments, target early user feedback, and accelerate feature shipping velocity. Maintain strict focus on mobile application security, cryptographic key safety, and client-side storage best practices appropriate for non-custodial banking platforms. Lead architectural discussions regarding local state management, data synchronization protocols, and offline-first mobile interactions. Help foster a collaborative, high-velocity engineering culture centered on craftsmanship, operational rigor, and personal initiative. Monitor application health, error logging, and performance telemetry post-deployment to ensure peak software stability for a global audience. Requirements At least 5 years of professional experience operating as a software engineer within production environments. Proven track record of architecting, launching, and maintaining complex React Native applications deployed to the Apple App Store and Google Play Store. Mastery of TypeScript and modern JavaScript, including deep understanding of asynchronous programming, type systems, and performance tuning. Strong product intuition and high design sensitivity, with a demonstrated passion for building sleek, responsive, and aesthetically polished user interfaces. Proactive, high-agency mentality with an ability to execute independently and solve ambiguous problems in a fast-moving environment. Physical presence in or willingness to work on-site out of office locations in either Madrid, Spain or Miami, Florida. Familiarity with client-side state management patterns and complex asynchronous data flows typical in high-scale mobile applications. Demonstrated capability to partner effectively with non-technical stakeholders, product leaders, and design teams. Nice to have Hands-on experience utilizing Expo frameworks, configuring mobile CI/CD build automation, and bridging native iOS or Android code modules. Comprehensive full-stack development experience with Node.js, microservice integration, and RESTful or GraphQL API construction. Working knowledge of EVM ecosystem architecture, decentralized finance mechanisms, or core blockchain principles. Active experience integrating generative AI coding assistants and automation tooling into daily software workflows to accelerate output. Skills & tools React Native TypeScript JavaScript iOS Android Node.js Expo Practical notes Tuyo operates as an early-stage venture backed by $5M in seed capital, currently operating with a lean core engineering group of 3 team members. Full relocation support and financial assistance are available for candidates relocating to either the Madrid or Miami office hubs. The organization equips engineers with a modern toolset, including a dedicated individual budget for AI-driven software development tools and services. The working arrangement requires an in-person physical presence at either the Madrid or Miami office, structured alongside roughly 25% flexible remote days. META Company: onhires Title: Senior Software Engineer Listed location: Madrid Job type: full_time #J-18808-Ljbffr onhires