Close

Backend Engineer

• Overhaul how Close syncs email and calendars. Our sync engine has run for a decade; we're making a serious, ground-up investment in its performance and reliability.
• Take voice agents further into the call. We own the live conversation layer for Chloe's calls, and there's a lot of work ahead expanding our voice agent capabilities and infrastructure.
• Solve inbound. So far Chloe makes calls; next she answers them. An inbound conversation can go anywhere — which raises real questions about specialized agents, a receptionist layer, and seamless call routing between them.
• Build native scheduling. Core calendar scheduling capabilities inside Close, plus more powerful scheduling for our agents.
• Design human orchestration of an agentic workforce. Agents create work for humans too — things to review, approve, respond to.
• Push connect rates and answer rates. Phone number pooling, local presence, branded calling, reputation monitoring.
• Move our streaming and event substrate forward. Kafka, Redis, pub/sub.

Senior Backend Engineer – Communications

• Ship code execution for the assistant. The assistant decides when writing code beats answering non-deterministically — today that's generating charts and tables in Python on the fly; next it's reusable user-defined tools and calling external APIs to pull in whatever data the task needs.
• Build the eval and observability layer that tells us when an agent is getting better. Unit tests don't cut it for non-deterministic output. We run evals and tracing (LangFuse and our own tooling) as the bar for shipping: if we can't measure it, we don't ship it.
• Push generated UI forward. The backend increasingly decides what the user sees — the LLM picks the right presentation (table, chart, widget) and renders it in the assistant, with a full-screen experience and stored, referenceable artifacts on the roadmap. Effectively: customers generate the reports we used to hand-build, one custom report at a time.
• Take Custom Agents from prototype to GA. Event-driven agents that act on what's happening inside the CRM in real time — an email lands, an agent drafts the reply from knowledge sources and context, the user approves. This is where we differentiate from the general-purpose assistants: we see the events, we have the context.
• Make deterministic and non-deterministic systems work together. Sales processes need steps that happen every single time; LLMs are bad at that. You'll help fuse our Workflows engine with agentic steps so customers get reliability where it matters and intelligence where it helps.
• Handle the edges that make agents trustworthy. What happens to a fleet of running agents when a customer's AI credits run out? Pause semantics, recovery, and making sure nothing places a hundred calls that were supposed to happen last week.
• Pick the right model for the job. We use many providers, test new models constantly, and are moving toward cost-aware routing — simple summarization jobs shouldn't run on frontier-priced models. You'll call when something is production-ready and when it's still a demo.

Senior Backend Engineer – Agents

Security Engineer

• Run our GRC program — then automate it.
• Own how customer data moves through our stack.
• Be the security gate for new tools and vendors.
• Make Close best-in-class at communicating trustworthiness.
• Coordinate product security audits.
• Investigate and clean up security incidents.
• Own our identity and device security.
• Run our employee security program.

Senior Backend Engineer – Communications

Senior Backend Engineer – Agents

Security & Trust Lead