Senior Full Stack Engineer

Updated in April 2026

About Upflow

Upflow builds the reference cash collection platform to help B2B companies get paid faster, more predictably, and with stronger customer relationships.

Today, the order-to-cash process is mission critical for businesses, yet it remains fragmented across tools, teams, and workflows. Collections, payments, and reconciliation are often manual, reactive, and disconnected from the rest of the business. Upflow brings this entire process into one system — combining data, agentic automation, collaboration, and financial services to turn receivables into a predictable and scalable engine.

We serve 500+ companies across 30+ countries, including Vercel, Lattice, Productboard, and are backed by leading investors including Y Combinator, Hedosophia, Hexa, and Lorimer. With teams across the US and Europe, we’re building a category-defining company at the intersection of finance, payments, and AI.

To learn more about what we do, visit upflow.io. For a behind-the-scenes look at how we work as a team, head to the Inside Upflow section of our blog at upflow.io/blog/inside-upflow.

About the role

You will join a small, efficient team based in Paris or working remotely that builds high-impact features for our users. You'll work on a wide range of topics, including workflow automation, payment processing, and communication features like email, calls, and letters. We invest significantly in AI to enhance our product with real use cases, and you'll play a key role in building our AI foundations.

We work in continuous deployment (10 deploys in production per day on average) and we value pragmatism, ownership, and growth mindset.

For more information about how we operate in the engineering team, please read this article.

What you will do

In your day-to-day, you will:

• Architect and implement complex, high-impact product features from start-to-finish.

• Collaborate closely with the product manager, the designer, and other engineers to translate business requirements into technical solutions.

• Ship clean, maintainable code to production daily.

• Participate actively in code reviews providing and receiving constructive feedback.

• Troubleshoot and debug complex product issues.

• Optimize application performance and ensure scalability.

• Help us define and improve our coding standards, development processes, and best practices.

• Stay up to date on new technologies and promote their adoption when appropriate.

Our current stack

• Frontend: Typescript, React, GraphQL

• Backend: Typescript, Node.js, Express, Postgres, and Redis

• Infra: GCP, Terraform

• Observability: Datadog and Sentry

• Github, Copilot, Claude Code, CircleCI

Who you are

• You have 5+ years of experience in software engineering.

• You have strong proficiency in Typescript, React and SQL.

• You value code simplicity and testing.

• You know how to prioritize in order to deliver quickly without sacrificing quality.

• You have good teamwork skills and enjoy providing and receiving feedback.

• You want to work in a startup environment that values excellence, autonomy, and ownership.

• You are fluent in English with strong communication skills.

• You are based in Paris, or live in Paris timezone.

Why join us?

Here what you’ll find at Upflow:

• Top-market compensation: €60k/yr - €90k/yr.

• International Mindset: We have offices in Paris and New York.

• Flexible working: On-site job in Paris in a hybrid office culture.

• Exciting moment: Opportunity to join early and contribute to the Engineering function from the ground up.

• All-star team: Extremely solid team with deep functional and domain expertise.

• Learning opportunity: Strong focus on learning and growing through education and professional development in hard and soft skills.

• Trusting environment: Hands-off management style. We have a strong culture of ownership and autonomy.

• Best in class perks: 35 paid days off, meal vouchers, cool offices, top-of-the-range equipment, great healthcare, and competitive salary and equity.

• Offsites: Regular offsites with the team, meetups, and strong connections to the startup ecosystem

Recruitment Process

1 - Screening call

It’s a discussion with our tech recruiter. We’ll get deeper into your expertise and know-how. We’ll also introduce you to Upflow in more details (vision, teams, stakes, ambition ...) and the goal is to see if it's a match!

2 - Technical interviews

• System design interview

In this interview, we'll explore how you design scalable systems and make architectural decisions. You'll be presented with a real-world scenario and we'll discuss trade-offs, data modeling, and how you'd handle scale and reliability.

• React Coding interview

This is a pair-programming session where you'll work through a real-world problem similar to what you'd encounter at Upflow. We'll collaborate on solving it together, giving us insight into how you approach technical challenges and communicate your thought process.

3 - Meet the team!

You’ll also meet up with at least two other peers so you can foresee yourself as part of this team. 😃

4 - Founder interview

Meet with Alex (co-founder & CEO). He will tell you everything about Upflow’s vision and values. It’s a privileged moment to ask questions, too.

*****

Diversity & Inclusion

At Upflow, we are committed to building a diverse and inclusive workplace. We encourage all individuals to apply, even if you don’t meet every qualification. Research shows that some candidates may hesitate to apply unless they meet every requirement. However, we believe that a variety of experiences and perspectives can bring value beyond the listed qualifications. If you’re excited about what we do and feel you could contribute, we want to hear from you