Senior Frontend Engineer (FR)

Senior Frontend Engineer

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, 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 Frontend Engineer to own and scale Lago's frontend application. You'll work closely with our Product and Backend Engineering teams to build and ship high-quality features, maintain our design system, and ensure the frontend is reliable, performant, and consistent at scale.

What You'll Be Doing

• Own and scale Lago's frontend app—reliability, performance, and feature delivery
• Co-design and build features with the Product and Backend Engineering teams
• Maintain and enhance our design system to ensure consistency across the app
• Improve monitoring and observability for frontend issues and bugs
• Work autonomously in a fast-moving environment and lead your topics to completion

Who You Are

• 5+ years of experience in frontend development
• Expert-level React skills
• Experience managing and scaling design systems in production
• Comfortable working autonomously in a fast-paced startup environment
• Proactive and ownership-driven—you lead your topics to completion without needing to be chased
• A genuine interest in open-source or developer tools is a strong plus

Who You're Not

• You're not someone who needs a fully scoped spec to start moving—you're comfortable with ambiguity and make progress anyway
• You're not siloed—you collaborate actively with Product, Backend, and Design and communicate clearly across teams
• You're not satisfied with "it works"—you care about performance, observability, and long-term maintainability
• You're not just a feature builder—you take pride in the systems and patterns that make the whole frontend better

Requirements

• 5+ years of professional frontend engineering experience
• Strong expertise in React
• Experience building and maintaining design systems in production environments
• Solid understanding of frontend performance, monitoring, and observability
• Strong written and verbal communication skills
• A mindset of ownership, curiosity, and continuous improvement

Nice to have

• Proficiency in GraphQL
• Experience contributing to or supporting open-source projects
• Familiarity with developer tools or infrastructure products
• Exposure to billing, fintech, or data-intensive frontend applications

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
• Remote-friendly: Work from anywhere in Europe
• Competitive package: Competitive salary and stock options
• Make an impact: Own the entire frontend of a 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: Remote Primary Location: Remote Europe Team: Product Engineering Work Type: Full Time/Permanent Contract Salary: 60,000-90,000 EUR

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