principal software engineer, eu

AboutDfns is the leading Wallets-as-a-Service (WaaS) platform, helping fintechs, institutions, and enterprises simplify digital asset management and securely onboard users onchain.Its API-first wallet platform unifies transaction management, workflow governance, key deployment, and third-party integrations into one secure operating system for blockchains. Built on advanced security and cryptography, Dfns is trusted by over 200 financial institutions and applications—including ABN AMRO, Broadridge, Fidelity, Zodia Custody, Banca Sella, Stripe, Moonpay, Circle, IBM, Deblock, and Gemini—and secures over $3 billion in monthly transactions.Founded in 2020, Dfns has raised $30 million from global investors such as White Star Capital, Motive Partners, Bpifrance, Coinbase, Wintermute, and Susquehanna. Originally incubated by Techstars and Station F in Paris, Dfns now operates globally with teams across the US, Europe, the Middle East, and Asia.Job DescriptionJoin a stellar team of leaders and experts in blockchain technology, cryptography, infrastructure, and security to build the backbone of blockchain wallet infrastructure for the next financial era. We're hiring a Principal Software Engineer to lead the design, development, and scaling of our core backend systems. In this role, you'll own critical projects while setting technical direction and ensuring our platform is fast, resilient, and secure. This is more than a coding role. You'll make key architectural decisions, drive engineering standards, and mentor senior engineers. You'll work with product, security, and leadership to align technical execution with company strategy and ensure our systems perform under the high-stakes demands of financial workflows.ResponsibilitiesPreferred ExperienceLead the design and development of scalable, secure backend services and APIs.Define and evolve architecture for databases, microservices, and integrations.Own mission-critical projects end to end, from requirements to production and iteration.Troubleshoot and resolve complex performance and reliability challenges at scale.Drive improvements to CI/CD, observability, and engineering processes across teams.Collaborate with leadership to shape roadmap priorities and long-term technical vision.Mentor engineers, promote best practices, and represent Dfns in client discussions.Requirements10+ years of backend software engineering, with leadership in fintech or blockchain.Mastery of TypeScript plus one or more systems languages (Rust, Go, C++).Proven track record building scalable APIs, infrastructure, and developer platforms.Deep expertise with databases (PostgreSQL, DynamoDB, NoSQL) and cloud (AWS).Strong knowledge of microservices, CI/CD pipelines, observability, and SSDLC.Familiar with applied cryptography, PKI, and secure backend architectures.Exceptional problem-solving, communication, and ability to influence technical direction.Recruitment ProcessProcessIntro call with Co-CEO (30 min).Personality and cognitive tests (45 min)Coding test in a language of your choice.Focus interviews with the hiring panel (180 min).Code reviewArchitecture reviewSecurity fundamentalsCulture check fitFinal interview with CTO (30 min).Reference calls and background checks.TermsTitle: Principal Software EngineerSalary: €120,000–200,000 per year (full-time)Equity: 150–300 stock options vested over 4 yearsBenefits: Healthcare, pension plan, and travel expensesLocation: European Union (remote-first, office optional)Equipment: MacBook Pro + essentialsAdditional InformationContract Type: Full-TimeLocation: ParisExperience: > 10 yearsPossible full remoteSalary: between 120000€ and 200000€ / year