Senior Backend Ruby Engineer
Overview
We're looking for a Senior Backend Ruby Engineer to contribute to Lago's core product and help scale our open-source billing infrastructure.
Job Description
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.
Responsibilities
- - Contribute daily to all parts of our codebase, using our development workflow
- - Tackle a wide variety of technical problems throughout the stack
- - Help grow the back-end team
- - Work with our Product Team and Front-end Engineers to understand customer needs and challenges
- - Come up with technical solutions to create and improve our best features and architecture
Required Skills
- - Strong knowledge of Ruby (at least 6 years hands-on experience)
- - Experience working with large volumes of data and event-driven environments
- - A genuine passion for Open-Source: if you've contributed to OSS projects or used OSS tools, let us know!
- - A real appetite for the early stages of co-creating a product and shaping Lago's future
- - Bonus: you've worked on billing or tax projects — whether implementing a billing system, maintaining it, or integrating it with business tools (e.g. a CRM, Finance tools)
Benefits
- - 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 (within +2h/-2h of CET), or join us in our Paris office
- - Competitive package: Competitive salary and equity for employees based in France
- - Make an impact: Your work directly shapes the product used by companies like PayPal, Synthesia, and Mistral.ai
About the company
Lago is an AI-native billing platform designed to help companies manage complex pricing models with transparency and flexibility. Founded in 2021 and headquartered in Paris, Lago provides a unified system for handling subscriptions, usage-based billing, and hybrid pricing structures, enabling businesses to support both self-serve and enterprise sales workflows in a single platform. The platform synchronizes customer and billing data across existing business tools such as payment providers, CRMs, accounting systems, and ERPs, helping teams maintain accurate financial operations without fragmented systems. As an open-source alternative to solutions like Stripe Billing, Chargebee, and Recurly, Lago focuses on giving engineering and finance teams greater control over metering, pricing logic, and billing infrastructure while scaling with growing product complexity.
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