Senior Backend Engineer – Communications (USA Only - 100% Remote)
Close moves 7 million minutes of call recordings, millions of sales emails, and a steady volume of SMS through our pipes every month. The Communications team owns that entire surface — and the job got trickier in the last year, because real-time calling is now a real-time AI problem. When a customer tells Chloe to make a call, everything that happens from that moment on — the live call, the conversation itself — is this team's.
We're looking for someone energized by both sides of the role: the distributed-systems challenges and the AI challenges.
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.
- Deeply experienced with email and calendar platforms. IMAP, sync protocols, calendar APIs, and the thousand edge cases of oddly configured enterprise mail servers. This is the experience that makes someone successful on this team fastest.
- Fluent in real-time and async distributed systems. WebRTC, WebSockets, queues, streaming. You've debugged a production incident where latency budgets didn't hold.
- Opinionated about AI in real-time workflows. You've built or used live transcription, voice agents, or in-the-loop AI features. You have a view on what's ready for production versus what's still a demo.
- At home in the gnarly bits. Telephony providers, codecs, retries, eventual consistency. You're drawn to the systems where edge cases actually matter. Deep Twilio or similar telepho...