About Lago

At Lago, we're on a mission to make billing simpler, more transparent, and more adaptable for SaaS companies.

As the leading open-source billing platform, we empower businesses to build flexible pricing models and scale with confidence. We've raised over $22 million in funding from top-tier investors including Y Combinator and FirstMark, reflecting strong confidence in our vision and growth.

Our platform has garnered over 9,000 stars on GitHub, a testament to our active and growing developer community. Companies such as PayPal, CoreWeave, Synthesia and Mistral.ai choose Lago for their billing.

We're a team of ambitious, focused individuals who work together to solve hard problems with excellence and accountability. At Lago, we value reliability and proactivity—we trust each other to own tasks, drive them to completion, and adapt quickly. While we encourage you to try fast and "fail fast", we also expect you to learn fast: make mistakes, but don't make the same one twice.

If you're excited by challenges and want to grow alongside a high-performing, supportive team, this is the place for you.

Overview

We're looking for a Senior Product Engineer to help drive Lago's core product forward — someone who obsesses over what gets built and why. You'll work at the intersection of engineering, product and design, owning features end-to-end: from shaping requirements with customers to shipping and iterating in production. This is a high-ownership role for someone who doesn't want to wait for a spec — they want to write it, then build it.

What you'll be doing

• Contribute directly to product decisions: Talk to customers and internal leads to understand their pain points and needs
• Own features end-to-end — from discovery and scoping through to shipping and monitoring in production
• Work closely with engineers and the GTM team to ensure customer needs are met and execution is high-quality
• Think clean, well-reasoned solution with a strong sense of quality and user impact
• Engage with the developer community — contribute to the open-source repo, respond to GitHub issues, and represent Lago's engineering values publicly

Who you are

• Comfortable working in ambiguous, fast-moving environments — you create clarity, you don't wait for it
• Strong communicator who can engage with customers, write a feature brief, and then go build it
• Ideally: experience in an early-stage startup where you've worn multiple hats

Who you're not

• You're not someone who waits for detailed topics — you shape the work as much as you execute it
• You're not indifferent to user outcomes — you care if the feature actually solves the problem
• You're not a siloed stakeholder — you collaborate across GTM, customers, and design as naturally as you collaborate with other engineers
• You're not intimidated by product conversations — you bring opinions, push back when needed, and take ownership of outcomes

Requirements

• 5+ years of software engineering experience, with a track record of shipping products that users love — not just systems that work
• Strong product and design instincts: you think about UX, business impact, and customer needs, not just technical correctness
• Experience building B2B SaaS products, ideally developer tools, APIs, or infrastructure

Nice to have

• Experience with open-source products or communities
• Some product design skills (Figma or equivalent)
• Familiarity with billing, fintech, or usage-based pricing models

Why Join Lago?

• Work with top-tier talent: Join a team that values excellence, ambition, and accountability
• Shape the future of fintech: Be part of a fast-growing company building the best open-source billing platform
• Hybrid work model: Work from anywhere in France or join us in our Paris office for a more hybrid setup
• Competitive package: Competitive salary and stock options
• Make an impact: Your work will directly shape the product used by companies like PayPal, Synthesia, and Mistral.ai

Ready to Build with Us?

If you're excited about joining a high-talent team to solve meaningful problems and help businesses thrive, we'd love to hear from you. Apply today and let's build something remarkable—together.

Location type: Hybrid

Primary Location: Paris office

Team: Product

Work Type: Full Time/Permanent Contract

Salary: 60,000–80,000 EUR per year

(Applicants must be based in the location specified for this role. Applications from other locations will not be considered.)