Senior Software Engineer - Backend (USA Only - 100% Remote)

Close is a profitable CRM company focused on helping teams sell more efficiently through innovative sales software. They are seeking a Senior Software Engineer to work on backend systems, utilizing Python and AI technologies to enhance their platform and improve user experiences.

Responsibilities:

• Build Close’s agentic platform and customer-facing AI experiences
• Own the voice, SMS, and email infrastructure powering Close
• Build the structured context layer that humans and agents both depend on
• Run the experiments and own the billing infrastructure that turn trials into paid customers

Requirements:

• A seasoned engineer. Python is our backbone, but perhaps you've worked across Go, Rust, or TypeScript. You pick the right tool for the problem rather than retreating to what you know. You've seen a variety of problems, can collaborate and self-direct
• Building AI. You've shipped LLM-backed features for real users and have a POV on where they're trustworthy, where they fall over, and how to get them production-ready when customers bet revenue on the output. We use Pydantic, Temporal, LangFuse, and other modern AI infrastructure tooling to power our agent platform
• 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. We fund the use of AI tools (Claude Code, Codex and other best-in-class developer tools) and treat learning and experimentation as part of the work
• A builder first. You'd rather get the first iteration of a feature in front of fifty customers than spend three weeks fretting over a perfect PR. You ship
• Opinionated about API design for modern software. You've shipped internet-facing APIs and you think about who's on the other end - apps, agents, humans poking around in docs - and what each of them needs
• 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