lago - Senior Backend Engineer

• 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) • You're not looking for a "just ship it" culture without quality standards — we care deeply about both speed and craftsmanship • You're not someone who works in silos — you actively collaborate with Product, Frontend, and your fellow engineers • You're not intimidated by ambiguity — early-stage problems don't always come with a clear spec, and you're comfortable navigating that • You're not allergic to context-switching — in a lean team, priorities shift and you adapt without losing momentum • 6+ years of hands-on experience in software engineering, with strong Ruby expertise • Experience working with event-driven systems and high-data-volume environments • Familiarity with background job frameworks (e.g. Sidekiq) and message queues • Comfort with REST APIs, webhooks, and data integrations • Strong written and verbal communication skills • A mindset of ownership, curiosity, and resilience • Experience contributing to or supporting open-source projects • Familiarity with billing systems, fintech, or developer tools • Experience with PostgreSQL, Redis, Kafka, or similar infrastructure • Exposure to containerised environments (Docker, AWS, CI/CD)