Senior Software Engineer - Fountain One

Role overview

You’ll join Fountain’s Platform team as a Senior Software Engineer within a compact platform squad (currently four engineers). The team builds the foundational systems that enable the Fountain ecosystem to ship dependable products at scale in an agent-first engineering environment.

Responsibilities

• Develop and ship platform capabilities powering both 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 both 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

Requirements

• 5+ years of professional engineering experience, primarily backend-focused, with a history of production-ready systems
• Expert-level systems design and strong architectural thinking
• Proven experience identifying and re-engineering misaligned systems
• Strong ability to evaluate technical trade-offs across UX, APIs, and code quality
• Demonstrated experience with agentic or LLM-based systems beyond consumer usage (e.g., LLMs on the critical path, agent tooling, or evals for regressions)
• Initiative and comfort operating in autonomous, ambiguous environments (no strict ticket queue)
• Excellent written communication for async collaboration across time zones

Nice to have

• Designed APIs/tools intended to be consumed by agents (e.g., structured outputs, deterministic surfaces, strong observability)
• Experience in early-stage product teams or startups
• Proficiency with event-driven architectures, monorepos, and/or platform-level observability
• Ability to describe LLM/agent failure modes and mitigations

Remote/in-person

Team members can do their best work from wherever they choose, with acknowledgement of the importance of in-person connections.