Staff Backend Software Engineer (US)

We are looking for a Staff Backend Software Engineer with 6+ years of experience to own and build core backend systems powering highly scalable SMS messaging infrastructure. You'll join a small, elite engineering team at a company that recently raised a $50M Series A and is expanding rapidly across enterprise, SMB, and political messaging verticals.

This is a rare opportunity to have massive technical impact at an early-stage startup delivering billions of messages per month. We need someone with strong career velocity who has built 0→1 products at high-growth startups (Pre-Seed to Series B) and thrives in a collaborative, fast-moving environment.

What you will do:

• Own and build core backend systems across routing, messaging, delivery, and automation infrastructure

• Design and ship scalable production services handling billions of messages per month across enterprise, SMB, and political messaging platforms

• Drive 0→1 product development - not just features, but entire product surfaces from scratch

• Collaborate closely with a lean engineering team

• Solve hard infrastructure problems at scale while moving quickly from idea to production