Senior Fullstack Engineer I - Platform Foundations

Responsibilities

• Design, build, and ship product features across the FAST platform, primarily in Python services and APIs.
• Own backend-dominant fullstack work end to end, including Svelte frontend surfaces.
• Build data models, integrations, and service architecture that turn an AI agent into a dependable product.
• Improve FAST’s reliability, maintainability, and architecture.
• Raise backend and product engineering quality through code review, design discussions, and hands-on pairing.
• Translate ambiguous product needs into concrete implementation plans and make clear architecture tradeoffs.
• Improve team delivery practices, including effective use of AI-assisted workflows.

Requirements

• 4+ years of hands-on fullstack engineering experience in a medium to large engineering environment.
• Strong backend experience, ideally with Python.
• Experience with modern frontend development and the ability to contribute to Svelte or a comparable framework.
• Comfort owning product features, service integrations, and implementation details across the stack.
• Solid grounding in distributed systems or systems-level engineering concepts.
• Strong written and verbal communication skills.
• Ability to work independently, navigate ambiguity, and drive work to completion.
• Track record of collaborating across backend, frontend, and machine learning disciplines.
• Interest in AI tools and agentic workflows that improve engineering speed, quality, and maintainability.

Nice to Have

• Experience building real-time or near-time OLAP applications.
• Production experience with Svelte or another TypeScript framework.
• Experience building products on top of LLMs or agentic systems.
• Exposure to data, analytics, business intelligence, or experimentation tooling.
• Experience with Go.
• Experience balancing product delivery with platform evolution.

Compensation and Benefits

• Base salary range: $162,198–$190,821.
• Equity for full-time employees.
• Dollar-for-dollar 401(k) match up to 4%.
• Medical, dental, and vision plans, including pet coverage.
• Up to $10,000 per year in continuing-education reimbursement.
• Employee resource groups.
• Flexible paid time off, 9 paid holidays, and a year-end week-long break.
• Paid parental leave and flexible return-to-work policies.
• One-time $2,000 Calvin Care Cash incentive for eligible employees welcoming new family members.
• Flexible remote or office work environment within the United States.