Principal Backend Engineer

Join us as Principal Backend Engineer in the Foundations domain and help scale the critical systems that power Qonto's 600,000+ customers - before they become bottlenecks. You'll drive company-wide backend initiatives spanning transactions, search, monetization, permissions, and integrations.

What you'll do

• Anticipate and solve scale challenges before they hit: You'll map technical risks across Foundations' core systems - ~600k daily transactions approaching 1B total, search indexing, billing - and drive the architectural work that keeps Qonto's growth ahead of its infrastructure.
• Lead broad, high-stakes technical initiatives: You'll own end-to-end programs spanning multiple teams, touching Legal, Risk, Compliance, and leadership, with real business consequences.
• Shape the platform's future: You'll identify where Foundations needs to invest next - from granular permissions to AI-native integrations - and translate those bets into technical roadmaps.
• Multiply the engineering org around you: You'll raise the bar for groups of engineers through mentoring, coaching programs, and technical enablement - not just one-on-ones.
• Bridge business goals and backend decisions: You'll connect company and customer needs to concrete technical plans and communicate them clearly to engineers and executives alike.

What we're looking for

• Large-scale backend architecture: You've designed and scaled high-volume systems - transactions, search/indexing, billing, or similar - under real growth pressure.
• Company-wide technical leadership: You've driven complex, multi-team initiatives that touched Legal, Risk, Compliance, and leadership, and you can tie every technical decision to a business outcome.
• Autonomous by default: You thrive in ambiguous environments, map ecosystems yourself, surface risks early, and propose initiatives without waiting for direction.
• Multiplier, not just contributor: You've raised the bar for groups of engineers through mentoring programs, documentation, or structured technical enablement.
• AI in your workflow: You use AI tools to accelerate how you architect, prototype, and communicate - and you're excited about what AI-native integrations could unlock for a platform like ours.

What we can offer you

• Scale Qonto's next chapter: Usage and data volumes are growing fast - you'll architect solutions before systems become bottlenecks, not after.
• The largest engineering domain at Qonto: Foundations spans ~110 backend engineers across internal tooling, monetization, integrations, transactions, permissions, and automation - it's genuinely Principal-scale scope.
• Complex, urgent, business-critical challenges: From search indexing trade-offs at 1B+ interactions to AI-native integrations, the technical problems here directly shape the product millions of customers use daily.
• Real ownership over technical direction: You'll identify what matters, propose the roadmap, and drive execution - with the autonomy to shape the domain's future.

Don't check every box? If you're excited by the scope and feel strongly about the mission, we'd love to hear from you anyway.