Forward Deployed Engineer

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 from top-tier investors who believe in our long-term vision. Our platform has attracted 7,000+ stars on GitHub, and forward-thinking companies like Mistral.ai, Together.ai, Groq, and Laravel rely on Lago to power their billing infrastructure. 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 experimentation and “failing fast” when needed, we also expect a steep learning curve: make mistakes, but never twice. If you're motivated by technical complexity, leadership impact, and building systems at scale—this is the place for you. About the role We’re hiring a Forward Deployed Engineer to join our Product team. This role is ideal for engineers who enjoy solving real-world customer challenges hands-on. You’ll work directly with users to support their implementation of Lago, guide them through architectural and product decisions, and build or adapt code that helps them succeed. You’ll act as a bridge between the user and Lago’s internal teams — writing production-level code, improving onboarding assets, supporting complex integrations, and channeling user feedback directly into our product development cycle. Responsibilities - Lead technical implementation efforts for strategic users — from initial architecture reviews to production deployment - Write scripts, integration templates, and lightweight services to support custom use cases - Contribute to Lago’s open-source SDKs, example repositories, and public documentation - Collaborate with users’ engineering teams to resolve complex integration challenges - Identify edge cases and implementation patterns, and feed them into product discussions - Build internal tooling and utilities that support faster and more robust deployments - Act as a hands-on technical advisor to both internal and external stakeholders Requirements - 3+ years of experience as a Software Engineer or in a technical role working with external users - Strong backend skills, especially in Ruby on Rails - Comfortable with PostgreSQL, Docker, Sidekiq, Clickhouse and event-based or asynchronous processing - Familiarity with RESTful APIs, webhooks, authentication flows, and OpenAPI specifications - Experience working with background jobs, queuing systems, and production environments - Excellent debugging and communication skills - Based in or willing to relocate to Paris, with in-office presence at least 3 days a week - Bonus: experience in billing infrastructure, SaaS metering, or open-source development

• Lead technical implementation efforts for strategic users — from initial architecture reviews to production deployment
• Write scripts, integration templates, and lightweight services to support custom use cases
• Contribute to Lago’s open-source SDKs, example repositories, and public documentation
• Collaborate with users’ engineering teams to resolve complex integration challenges
• Identify edge cases and implementation patterns, and feed them into product discussions
• Build internal tooling and utilities that support faster and more robust deployments
• Act as a hands-on technical advisor to both internal and external stakeholders

• 3+ years of experience as a Software Engineer or in a technical role working with external users
• Strong backend skills, especially in Ruby on Rails
• Comfortable with PostgreSQL , Docker , Sidekiq , Clickhouse and event-based or asynchronous processing
• Familiarity with RESTful APIs , webhooks , authentication flows , and OpenAPI specifications
• Experience working with background jobs, queuing systems, and production environments
• Excellent debugging and communication skills
• Based in or willing to relocate to Paris, with in-office presence at least 3 days a week
• Bonus: experience in billing infrastructure, SaaS metering, or open-source development