Senior Software Engineer - Fountain One
Software Engineering
Lisbon, Portugal
Posted on Aug 28, 2026
Fountain builds workforce management software for the world's largest hourly employers. We are an agent-first engineering organization where coding and review agents are integrated into our daily workflow. Our platform team builds the critical systems that enable engineers and agents to ship dependable products at scale. What You’ll be Doing:- Ship platform capabilities across all customer and internal products- Own performance, security, and stability for high-traffic production systems- Enhance agentic systems, including coding agents and observability tools- Lead architectural decisions for human and agentic interfaces- Design reliable code, APIs, and contracts for humans and agents- Collaborate with product and engineering teams to deliver customer impact- Work autonomously with product managers and designers- Identify problems, ship fixes, and own outcomes like an early-stage product team What you bring and Nice to have:- 5+ years backend-focused engineering; expert systems design; strong trade-off/UX/API/code judgment- Experience with agentic/LLM systems and evals; initiative; excellent async communication- Designed APIs/tools for agents; early-stage/startup experience; event-driven architectures/monorepos/observability