Senior Software Engineer

WebHosting; France; Hybride; EUR 95 000 - 130 000; Plein temps

Résumé du poste

Upsun is a cloud application platform used by hybrid teams worldwide. We design scalable billing backends in Go, focusing on reliability, security, and observability.

You will own complex features end to end, collaborate across Finance, Product, and Support, and mentor peers in a distributed, remote-first culture. As a Senior Software Engineer, you will work on invoicing, taxes, usage reporting, and integrations to external systems, always aiming to improve system quality and performance while

Qualifications

• Deep professional backend development in Go, building services in distributed systems.
• Experience designing and delivering billing-related features and services.
• Strong focus on reliability, observability, and security in financial systems.

Responsabilités

• Design, build, and maintain billing backend services and API integrations.
• Own complex features end to end from design to production.
• Make sound architectural decisions balancing short-term delivery and long-term reliability.
• Troubleshoot and fix root causes across distributed services and external APIs.
• Mentor engineers, review code, and uphold quality standards.
• Collaborate with Finance, Product, Support, and other teams across time zones.

Connaissances

Go

Distributed systems

Code review

Mentoring

Async communication

Billing systems

Outils

PostgreSQL

MySQL/MariaDB

REST APIs

API integrations

Description du poste

Upsun is the cloud application platform humans and robots love. It is built for today’s hybrid teams, where AI agents write and test code and humans focus on solving the problems that really matter. Developers, DevOps engineers, and platform teams use Upsun to build, ship, and scale confidently without wrestling with backend infrastructure. We give you your time back. You get:

• Predictable performance, even at scale
• Secure, compliant environments by default
• Real-time observability and profiling built in
• Cloning, configuration, and provisioning in seconds
• AI-ready features that plug directly into your stack

The name says it all. “Up” means uptime, reliability, and acceleration. “Sun” reflects our follow-the-sun-support, a 24×7, globally distributed support team keeping the lights on while you rest. Our core belief is that software should power brighter solutions and greater innovation.

Upsunners are a remote, global workforce, and we thrive in a multicultural team. We are committed to open source and an open, welcoming environment. Our team spans the globe and the experience spectrum.

What’s our commonality, our cultural fabric? A curious spirit and a thirst for knowledge; an eagerness for innovative ideas and cultures. We believe we can build anything together in an environment that frees you to do your best work.

Our values:

We make a positive impact.

We aim for the stars.

We care for each other.

Impact of a Senior Software Engineer

As a Senior Software Engineer at Upsun, you will design and build the backend services behind our customers’ billing, and help the engineers around you do their best work. Billing is your main focus: invoices, taxes, usage reporting, and the integrations that connect our platform to the commercial systems behind it.

You will own complex components end to end, make the design decisions behind them, and spot where they can be improved. Working closely with Finance, Product, and Support, you will turn commercial requirements into reliable services. This is a hands‑on role: most of your time goes into designing and writing code that customers rely on every time they’re billed.

What to expect

Design and build billing services: Design, build, and maintain backend services and API integrations in Go that connect our platform to external billing systems.

Own complex features end to end: Lead the design and delivery of usage-based billing features such as usage aggregation, estimates, usage alerts, and invoicing, from technical design to production.

Make sound design decisions: Shape the architecture of the components you own, weigh trade‑offs, and balance short‑term delivery with long‑term reliability.

Solve hard problems: Troubleshoot complex issues across distributed services and external APIs, and fix root causes, not just symptoms.

Improve what you own: Spot gaps in reliability, security, observability, or process within your area, then propose and deliver practical fixes.

Protect customers and data: Contribute to anti‑abuse measures and apply security best practices to sensitive customer and payment data.

Mentor and review: Support other engineers through code review, pairing, and mentoring, and help keep the bar for quality high.

Work across teams: Partner with Finance, Product, Support, and other engineering teams, communicating clearly and asynchronously across multiple time zones.

Go experience: Deep professional backend development in Go, building services in distributed systems.

System design: Experience designing backend systems and making architecture decisions that held up in production.

Relational databases: Strong experience with relational databases such as PostgreSQL or MySQL/MariaDB, including data modeling, migrations, and performance.

Complex integrations: A track record of integrating third‑party APIs where you don’t control the contract, the rate limits, or the uptime, with strong instincts for idempotency, retries, and consistency.

Accuracy and testing: Experience in domains where correctness matters, such as billing or payments, and a commitment to testing failure paths.

Security awareness: A solid understanding of common vulnerabilities and of security considerations in payment and billing systems.

Mentoring: Experience mentoring engineers or guiding technical work on a team while staying hands‑on.

Interest in billing: You enjoy working on billing and financial systems and want to make them your focus.

Clear async communication: You write clearly and can build agreement across a distributed team.

Bonus

Where we hire

At Upsun, remote work isn’t just a trend – it’s our foundation. The freedom of remote work with the support of a diverse, global team has been our successful model for over a decade. Our culture celebrates flexibility and collaboration, and while we have team members in over 30 countries around the globe, we are currently focused on hiring for this role in Canada, France, Germany, Spain, the United Kingdom, and the United States. Although we’re unable to provide visa sponsorship at this time, we welcome applications from all qualified candidates who are legally authorized to work in these countries.

How we hire

We know that a great hire won’t meet every requirement that we’ve outlined. If you can see yourself elevating the team, we want to hear your story. Few of us would be here had we not taken a chance.

You can expect 4 interviews on Google Meet to follow the order below. Should you successfully move through the entire process you will have the opportunity to meet with a variety of Upsunners. Our goal is to ensure you can make the most informed decision on whether this role, and our culture aligns with what you’re looking for in your future working environment.

All roles require background checks.

A product you can believe in– Join us in transforming how businesses build and manage web applications, driven making a positive impact as a proudB Corp.

An Award-Winning Workplace– We’ve been recognized by Forbes’ Top 30 Companies for Remote Jobs and France’s Best Workplaces for Women.

A culture that values your voice– Join a flexible, open, and inclusive work environment where your voice is encouraged, and your ideas shape our growth and evolution.

A global team– Collaborate with colleagues from diverse backgrounds across the world, embracing different perspectives

Benefits and perks– Make the most of what matters to you