We’re looking for a Lead Backend Engineer (C#/.NET, Blockchain, Crypto Wallets) to join our core team.
You’ll design and build scalable distributed systems, create APIs and SDKs, and shape the architecture of our self-custody wallet. You’ll integrate with blockchain networks, smart contracts, custody solutions, and Fireblocks API, ensuring security and scalability at the core of our product.
As the lead for the Self-Custody module, you’ll own one of the most critical parts of our wallet — where technical excellence and product vision meet. This is a chance to become the technical owner of a product area and influence the company’s roadmap.
We need someone strong in C#/.NET Core, multithreading, microservices, and resilient architectures, with a product mindset and the drive to take ownership in a fast-moving startup.
If you’re passionate about crypto, fintech, and AI-assisted development tools, this role is for you.
Key Responsibilities: * Develop and lead the Self-Custody module, a core component ensuring secure and user-friendly crypto asset management. * Design and implement scalable distributed systems, APIs, and SDKs to power next-generation crypto wallet infrastructure. * Architect resilient microservices with a focus on performance, scalability, and fault tolerance. * Integrate with blockchain networks, custody/self-custody solutions, and Fireblocks API. * Collaborate closely with Product, Frontend, and DevOps to translate business ideas into technical solutions. * Take ownership from concept to production: propose, design, and deliver solutions without waiting for rigid specs. * Contribute to product discussions and shape the roadmap by bringing forward technical and architectural insights. * Experiment with new protocols, blockchain integrations, and AI-assisted development tools to boost efficiency.
Ideal Candidate: * Thinks in products, not just code. * Leads ownership of the Self-Custody module. * Works independently, driving solutions end-to-end. * Collaborates closely across product and tech teams. * Adapts quickly to a fast-changing startup environment. * Has a strong passion for crypto and fintech. * Proactively brings ideas and explores new tech. * Balances clean code with delivery speed.
Required Skills: * Strong expertise in C# / .NET Core (with Entity Framework, gRPC, Blazor, Microservices). * Solid knowledge of multithreading, high-load distributed systems, and SOLID principles. * Hands-on experience with blockchain technologies: wallet integration, smart contracts, custody/self-custody. * Proven experience with Fireblocks API and platform integration. * Proficiency with PostgreSQL, Docker, Kubernetes. * Experience in designing APIs, SDKs, and distributed architectures.
Nice to Have: * Familiarity with advanced architecture patterns and strategies for fault-tolerant systems. * Experience with resilient infrastructure in high-availability environments. * Comfort with modern IDEs and productivity tools (ReSharper, JetBrains suite). * Curiosity and hands-on experience with AI development tools (Copilot, Cursor, ChatGPT, Codeium).
What We Offer: * Full-time, fully remote work with no location restriction * Flexible working hours to suit your schedule. * Paid Vacation: 18 working days per year, prorated based on the calendar year * Paid sick leave * 8 additional working days off for National Holidays. * Birthday Gift from Company * Zero Fee SimpleApp Wallet * Additional Anniversary leave for 2 years and more.
About Simple.app
Simple is a next-generation stablecoin wallet designed to make digital finance truly usable. With over 2.5 million users across 245+ countries, Simple empowers individuals and businesses from freelancers to global teams to send, store, spend, and grow their money using stablecoins, with the ease and familiarity of traditional finance.
Headquartered in Dubai and regulated in the EU, Simple bridges the gap between crypto and real-world financial tools through intuitive product design, seamless fiat integrations (including IBAN and SEPA), and a secure self-custodial infrastructure.
At its core, Simple stands for financial freedom without borders. The company’s mission is to make crypto simple, trusted, and accessible so people everywhere can manage their money on their own terms.
