Forward Deployed Engineer in Paris - Lago

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