Product Engineer (AI Agents for Growth)

Lago is the leading open-source billing platform for usage-based pricing, powering billing for companies like PayPal, CoreWeave, Mistral AI, and Synthesia (YC S21).

The role involves transforming working AI prototypes into a production-grade multi-agent platform for go-to-market operations. These agents run on Claude Code, connect to CRM, Slack, and email, and have been iteratively refined with real production data over several months.

Key Responsibilities:

• Decompose monolithic AI skills into composable agents with clear inputs, outputs, and failure modes — built on Claude Code and Claude Agent SDK
• Make the system multi-user with differentiated permissions, views, and triggers with shared state layer
• Implement automated feedback loops where system corrections inform agent calibration
• Extend to additional workflows (deal automation, risk scoring, competitive monitoring)
• Ship production systems with instrumentation and continuous improvement

Required Skills:

• Production systems experience with APIs, databases, async workflows, CI/CD
• Hands-on LLM development (Python or TypeScript)
• Understanding of agent architectures (chains, routers, autonomous agents)
• Experience with tool-use APIs, structured outputs, and AI reliability engineering
• Product thinking focused on workflows

Nice-to-Have: HubSpot or CRM familiarity, Slack/Gmail API integration, webhook-driven architecture, evaluation/benchmarking frameworks

Salary: EUR 60,000 - 80,000

Location: Remote (France, Spain, Germany, Italy, UK)

Success Metrics:

• 3 months: First system decomposed, 2+ team members using autonomously
• 6 months: Self-improvement live, new workflow in production
• 12 months: Platform core to GTM operations