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

Key Highlights

• Communications. Own the voice, SMS, and email infrastructure powering Close — Twilio, WebRTC, WebSockets, AssemblyAI, ElevenLabs, and more. You’ll help build our voice, messaging, and conversational AI agents while scaling real-time AI across calls, email, and calendar sync infrastructure.
• 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.
• 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.