Senior Backend Engineer – Agents (USA Only - 100% Remote)
We shipped our first agent, Chloe https://close.com/chloe, in 2026. The Agents team owns the platform underneath: the agent core, the eval and observability layer, the MCP surface that external agents (Claude, ChatGPT, ElevenLabs, n8n) operate Close through, and the orchestration that ties it together.
The team is running three major streams right now: Voice Agents, the LLM-powered chat assistant, and Custom Agents. Most of the engineering problems here didn't exist a year ago. We're figuring them out in code, in production, in front of 11,000 paying customers.
One thing to know up front: we do move people between teams as the work shifts. Most engineers here end up on more than one team over their time at Close — this team is where you'll start, but over time you'll likely have the opportunity to work on many different projects.
This role is open at multiple levels — Software Engineer, Senior, and Staff. You don't need to pick one when you apply: we'll calibrate together during the process.
YOU ARE
- A seasoned engineer. Python is our backbone, but perhaps you've worked across Go, Rust, or TypeScript. You pick the right tool for the workload rather than retreating to what you know.
- AI-native in production. You've shipped meaningful, impactful agentic features to users. You have opinions on retrieval, evals, tool design, context engineering, and where the current frontier models fall over.
- Working with AI in your day-to-day. You use AI tools in your own workflow to ship faster, write tighter code, and reason about unfamiliar parts of the codebase. You have a POV on where they help and where they get in the way.
- A builder first. You'd rather get a sloppy v1 in front of fifty customers than spend three weeks on abstractions. You ship.
- Battle-tested. You've debugged incidents where latency budgets didn't hold, owned a system everyone else relied on, or carried a pager for something with real customer impact.
- Close to the research. You re...