Senior Backend Engineer

Location: Paris, France Workplace: Hybrid We’re a team of experts pushing the limits of what’s possible, united by our common goal to unlock true freedom through digital ownership, making technology accessible for all. We believe in a world where users, creators and enterprises manage their value with ownership and freedom. Our curiosity drives us to innovate, empowering individuals on a global scale. We believe change is constant and our team moves forward as one, with a culture of problem-solving where every employee is empowered and supported to challenge tradition and create solutions. Our mission is simple: to make self-custody accessible and give people the keys to their own financial futures. If you want to make a true impact, we want you to join us at Ledger. At Ledger, we’re proud to be the global platform for digital assets and Web3, with over 20% of the world’s crypto assets secured through our Ledger devices. With our headquarters in Paris, and offices in Vierzon, Grenoble, Montpellier, London, Portland, Geneva, Zurich and Central Singapore, we have a team of around 600 professionals developing a variety of products and services to enable individuals and companies to securely buy, store, swap, grow and manage crypto assets – including the Ledger hardware wallets line with more than 7.5 millions units already sold in 200 countries.   The team To sustain the company's growth, Ledger is looking for a Senior Scala Backend Engineer to join the Cloud Wallet team. This team builds and operates the backend services that power blockchain account management, transaction processing and on-chain data aggregation across all Ledger wallet surfaces, from Ledger Live to Ledger Enterprise, the custody platform used by financial institutions. Every client transaction goes through these services, and so does every new blockchain Ledger supports. We believe in the power of functional programming to build robust and scalable platforms. We take time to share, challenge, and grow together through bi-weekly knowledge-sharing sessions, meetups, conferences, and open source contributions.   What you’ll be doing - Design, build and operate the Scala services that connect Ledger wallets and the Ledger Enterprise platform to blockchain backends: account creation, operation history, transaction crafting, broadcast and lifecycle tracking. - Lead new blockchain integrations end to end, from the integration design (ADR) to production, across account-based, UTXO and privacy-preserving chains. - Own production quality on your scope: SLIs and SLOs, observability, distributed tracing. Take part in the firefighting rotation and drive incidents to resolution, including those raised by institutional clients. - Define clear contracts with the Coin Integration and Ledger Enterprise teams, for example where UTXO selection lives or how transaction states are exposed to consumers. - Write and review ADRs, challenge designs, and raise the bar on code quality, testing (including end-to-end on testnets) and technical debt management. - Work in an AI-native way: use coding agents daily, write the specifications, constraints and verification that let them deliver safely, and contribute to the team's AI tooling. - Mentor other engineers and share your knowledge across the Backend Blockchain community.   You will collaborate cross-functionally with: - The Coin Integration team for coin modules and new blockchain integrations. - The Ledger Enterprise team, main consumer of the team's services for institutional custody. - The Ledger Wallet, Ledger Button and Wallet XP teams as consumers of the team's backend APIs. - The Blockchain platform team for data model alignment, indexing and event streaming. - The Infrastructure and SRE teams for deployment, reliability and scalability. - The Security team (Donjon) for vulnerability analysis and remediation. - The Product team for roadmap prioritization and customer-driven requirements.   What we’re looking for - 5+ years of backend engineering, with real production ownership of distributed systems. - Strong production experience - Interest for Scala and functional programming practice - Hands-on blockchain integration experience: transaction lifecycle, fees, finality, reorgs, on at least two models among account-based, UTXO and privacy-preserving chains. - Experience with event-driven systems and data infrastructure (PostgreSQL, RabbitMQ, NATS or equivalent) and with observability tooling (Datadog or equivalent). - Able to diagnose an incident across several services and own the outcome, from root cause to fix in production. - Comfortable reading and contributing to TypeScript code, as the team works on a polyglot stack. - Daily use of AI coding tools, with a critical eye on their output. - Clear written communication in English, especially for design documents and incident reports. At Ledger, we are dedicated to continually investing in our employees which is why we offer more than just salaries; we provide comprehensive compensation packages that include a wide range of benefits. Here are some of the benefits you can look forward to: - Flexible work options - Our hybrid policy allows employees to work from home up to 3 times per week - Health & Wellness support - Health and Life Insurance. - Financial growth opportunities - Employees can become shareholders in Ledger as well as other financial benefits depending on your country of work. - Commuter allowance - Ledger offers a commuter allowance to contribute to your preferred means of transportation. - Learning & Development - A comprehensive suite of training solutions providing a personalised learning experience for every employee. For regionally specific benefits, your Talent Acquisition contact will be able to provide you with more information. We’re committed to building an inclusive hiring process. If you need any adjustments or accommodations, just let us know, we’ll do our best to support you.