Senior Software Engineer

About

Dfns 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 Description

Join 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 Senior Software Engineer to design, develop, and scale the core backend services of our platform. You’ll own critical projects, from APIs and microservices to databases, integrations, and developer tooling, ensuring they’re fast, reliable, and secure. This role requires both hands-on engineering and strong collaboration as you’ll work with product, security, and engineering to turn complex requests into elegant, production-ready systems. You’ll be expected to move beyond writing code, i.e., contributing to architecture decisions, improving development processes, and keeping our infrastructure resilient under real-world financial workloads.

Preferred Experience

Responsibilities

  • Design, build, and maintain secure, scalable backend services and APIs (REST).

  • Architect databases and microservices for performance, reliability, and growth.

  • Own projects end to end: from requests, implementation to production and iteration.

  • Troubleshoot complex issues, resolve performance bottlenecks, ensure resilience.

  • Contribute to CI/CD pipelines, observability, and overall engineering excellence.

  • Collaborate with product, security, and leadership on roadmap and technical direction.

  • Document systems, share knowledge, and support client-facing discussions.

Requirements

  • 8+ years of backend software engineering experience in fintech or blockchain.

  • Strong in TypeScript, plus ideally at least one low-level language (Rust, Go, C++).

  • Proven track record building scalable APIs, infrastructure, and developer tools.

  • Expertise with databases (PostgreSQL, DynamoDB, NoSQL) and AWS services.

  • Skilled in microservices, CI/CD pipelines, observability, and SSLDC practices.

  • Familiar with applied cryptography, PKI, and backend security fundamentals.

  • Strong problem-solving, clear communication, and ability to deliver under pressure.

Recruitment Process

Process

  • Intro 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 review
    • Architecture review
    • Security fundamentals
    • Culture check fit

  • Final interview with CTO (30 min).

  • Reference calls and background checks.

Terms

  • Title: Senior Software Engineer.

  • Salary: $160,000-240,000 per year (full-time).

  • Equity: 100-200 stock options vested over 4 years.

  • Benefits: Healthcare, 401K, and travel expenses.

  • Location: US or EU (remote-first, office optional).

  • Equipment: MacBook Pro + essentials.

Additional Information

  • Contract Type: Full-Time
  • Location: Paris, New York
  • Experience: > 7 years
  • Possible full remote
  • Salary: between 160000$ and 240000$ / year
Apply Now

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