What are the responsibilities and job description for the Senior Software Engineer position at Cassidy?
Company
Cassidy is an AI agent and automation platform for non-technical knowledge workers. By connecting to a company's knowledge where it lives and building intuitive core primitives, Cassidy lets non-technical teams automate large swaths of busy work, freeing them up to do the work that really matters.
About the role
We have 5 engineers and no product managers. Engineers own product decisions, work directly with customers, and ship daily. We're looking for someone who can be the first among equals on the engineering team: the person who takes on the hard architectural decisions, owns system reliability as we scale enterprise customers, and raises the bar for the whole team.
You'll work across the full stack building the core platform: agents, workflows, knowledge bases, and integrations. The work right now is a mix of complex product engineering (building agentic harnesses that can scale, workflow orchestration, enterprise permissioning systems), platform reliability as we onboard larger customers, and applied AI engineering that's genuinely cutting edge.
What You’ll Do
- Own core systems end to end: design, build, ship, and keep them running
- Be the senior technical voice in the room on architecture and tradeoff decisions
- Improve platform reliability and scalability. We're growing fast and need someone who's owned production systems under real load before.
- Make product decisions. Engineers here decide what to build, not just how.
- Work on applied AI engineering: LLM orchestration, agent systems, tool calling. This stuff changes monthly and we're building at the frontier.
Who You Are
- Full stack experience (we're end to end TypeScript: Node, React, Postgres)
- You've been at 2-3 companies and this isn't your first startup. Ideally you were early at a company at least once.
- You've owned complex systems over time and have seen what happens when architectural decisions play out over years, not weeks
- You have strong product instincts. You think about what to build, not just how.
- You can own something end to end without needing someone to break it down for you
- You're motivated by impact: applying what you know to build something real, not just chasing the most technically interesting problem
- CS degree or equivalent
Nice to haves
- Experience with infrastructure and reliability at a scaling startup
- Experience with AI/ML systems in production
- Founder or co-founder experience, even if it didn't work out
Details
- NYC, in-office 4-5 days/week
- Competitive salary meaningful equity