Product Engineer (Core Product)

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 or product 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.

Job Details

• Location type: Remote
• Primary Location: Remote France (Ideally Paris)
• 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.)