Senior Full-Stack Engineer (Ruby, ReactJS)

Qonto; Paris; Remote; EUR 90,000 - 130,000; Full time

Job summary

Qonto, a leading European fintech, is hiring a Senior Full-Stack Engineer for its Identity Verification team. You will help turn the KYC flow into a provider-agnostic service that any Qonto team can use, with 60% backend focus and the web as your second surface.

You’ll work across backend and web, integrating providers and their SDKs, and you may ship Ruby primarily, with Go and React involved. You report to Nicola, Engineering Manager, and join a diverse, fast-moving culture that values

Qualifications

• Back-end services experience in production environments.
• Experience shipping web code with React and maintaining/ scaling applications.
• Experience integrating external providers or SDKs.
• Ability to work across backend and web with a provider-agnostic mindset.
• Ruby experience is a plus or willingness to learn.

Responsibilities

• Make identity verification provider-agnostic by consolidating to a single service.
• Improve KYC conversion by working across backend and web.
• Own the web side of provider integrations and ensure stability as usage scales.

Skills

Backend experience

React on the web

Third-party integrations

Range across the stack

Ruby, or willingness to learn

Job description

Our mission and customers: We are creating the freedom for SMEs to succeed by delivering Europe's leading finance workspace with banking at its core, augmented by financial tools. We are proud to be rated 4.8 on Trustpilot based on 55,000+ reviews. Our culture puts customer satisfaction at the core of what we do, as proven by our Net Promoter Score of 75 (more about our culture here).

Our journey: Founded in 2017 by Alexandre and Steve, Qonto has grown to 1,700 Qontoers serving over 750,000 customers across 8 European countries. We have been profitable since 2023, and we are just getting started.

Our beliefs: We hire for skills and potential. With 80+ nationalities, 45% women, of which 56% of women in our leadership team, diversity isn't a program; It's who we are. We've built a discrimination-free hiring process because the best teams are built on merit.

AI at Qonto: AI is deeply embedded in how we work (here) - Every Qontoer gets unlimited access to the best AI tools. We want people who experiment without waiting for permission, push AI beyond the obvious, know when to trust it, and when to question it.

Location: You can choose to work in a full-remote mode as long as you're living in either France, Italy, Germany, Serbia, or Spain.

Join us as a Senior Full-Stack Engineer in our Identity Verification team to turn our KYC flow into a service that works with any provider, and to help more customers get from KYC started to KYC submission. 60% of your time goes on the backend, with the web as your second surface.

You will report to Nicola, the Engineering Manager of the Identity Verification team.

What You’ll Do

• Make identity verification provider-agnostic: Replace today’s tightly coupled solution with one service that any team at Qonto can use, whichever provider runs the checks. This is mostly Ruby (90%), with some Go (10%)
• Improve KYC conversion: Work across backend and web on the path from KYC started to KYC submission, our main objective for the team.
• Own the web side of provider integrations: Load provider SDKs in the browser, handle the errors they return, and keep the web part running as usage scales. Expect roughly half your time on web at first, moving towards 30% as the work shifts to the backend.

What We’re Looking For

• Backend experience: You’ve built and run backend services in production, and you’re at ease being backend-first.
• React on the web: You’ve shipped production web code with React, and you can handle maintenance and scaling work on an existing application.
• Third‑party integrations: You’ve integrated external providers or SDKs, and you know how to design so that a single provider doesn’t lock you in.
• Range across the stack: You’ll own changes across backend and web, partnering with our staff web engineer on architecture and complex integrations.
• Ruby, or the will to learn it: Ruby experience is a plus, not a requirement.

What We Can Offer You

• Platform work with real users: You build infrastructure behind KYC, the first step every customer takes with Qonto, and you see its effect in the conversion numbers.
• Build reliable verification flows: Handle provider failures and retries, improve observability, and help the team operate integrations safely in production.
• A design problem with real trade-offs: We work with several verification providers, each with its own SDK, errors and behaviour. You’ll design the layer that makes them interchangeable, and untangle today’s tightly coupled solution so that changing a provider no longer touches every consumer.
• A platform other teams build on: KYC is our first internal customer, with other teams potentially following, such as Security for password reset checks. You'll build reliable APIs that other Qonto teams can depend on, while making the verification journey smoother, clearer, and more reliable for our customers.
• Support from day one: An onboarding buddy from week two, and a weekly one-to-one with your manager.

Your future manager

Your manager will be Nicola, our Engineering Manager.

• His path? Nicola spent four years at Satispay, progressing from Backend Engineer to Engineering Lead, managing 6-8 engineers. He helped scale their SEPA payment infrastructure from a few thousand to over a million transactions per week before joining Qonto as an Engineering Manager.
• What does he bring to the team? A people-first leadership style focused on helping engineers grow. He sets clear expectations, encourages autonomy and learning through experimentation, and values direct feedback and open discussions. His goal is to build confident, independent engineers who take ownership of their work.

At Qonto, we understand that true diversity isn’t just about ticking boxes on a hiring checklist. Apply regardless of the boxes you tick — who knows? You may have the missing piece of the puzzle we’ve been searching for all along.

On average, our hiring process lasts 20 working days.