Staff Backend Software Engineer – High-Scale Messaging (SF) Location: San Francisco, CA — On-site, 5 days/week Employment Type: Full-time Salary: $225K–$300K base Equity: Competitive equity Visa Sponsorship: Not available About This Role We are looking for a Staff Backend Software Engineer with 6+ years of experience to own and build core backend systems powering highly scalable messaging infrastructure. You'll join a small, talent-dense engineering team at an early-stage technology company that recently raised a $50M Series A and is expanding rapidly across enterprise, SMB, and political messaging. The platform handles billions of messages per month, creating complex infrastructure and scalability challenges for the engineering team. This is a rare opportunity to have massive technical impact at an early-stage startup with meaningful traction. We need someone with strong career velocity who has built 01 products at high-growth startups from Pre-Seed to Series B and thrives in a collaborative, fast-moving environment. What Will You Be Doing? • 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 01 product development — not just individual features, but entire product surfaces from scratch. • Solve hard infrastructure problems at scale while moving quickly from idea to production. • Own technical projects end-to-end with significant independence. • Collaborate closely with a lean engineering team as the company continues to scale. What We're Looking For • 6+ years of backend-heavy software engineering experience. • Experience working in high-growth, early-stage startups, particularly from Pre-Seed through Series B. • Experience building entire products from 01. • Professional experience with Node.js and TypeScript. • Experience with AWS SQS or similar queue-based infrastructure. • Degree in a technical field. • Ability to own technical projects end-to-end with minimal hand-holding. • Strong career velocity. • Strong collaboration skills. • Ability to translate complex technical concepts into plain English. Backend engineering is the priority for this role. For candidates with full-stack backgrounds, experience weighted toward backend development is preferred. Frontend development experience is a plus. Tech Stack Node.js, TypeScript, AWS, SQS, Queue-based infrastructure Node.js, TypeScript, and AWS experience are strongly preferred. Engineers with experience in other JavaScript tech stacks may also be considered if they demonstrate strong engineering ability. Work Environment This is a highly collaborative, fast-moving startup environment where engineers are expected to take significant ownership and move quickly from idea to production. The engineering team currently consists of approximately 8 engineers and is expected to grow to around 15 as the company scales. The role is on-site 5 days per week in San Francisco. Candidates outside the area must be willing to relocate. Compensation & Equity • Base Salary: $225K–$300K • Competitive equity About the Company This early-stage B2B technology company is building AI-first infrastructure for high-scale outbound communications, allowing enterprise brands to deliver campaigns at massive scale. The company's technology supports billions of messages per month across multiple lines of business, including enterprise, SMB, and political messaging. Founded in 2023, the company has approximately 20 employees and has raised approximately $60M in total funding, including a recent $50M Series A from top-tier investors. The company is scaling quickly in a massive market with meaningful traction and multiple new lines of business. With a small team and growing engineering organization, this is an opportunity to have significant influence over the systems and products being built. Work Authorization Visa sponsorship is not available for this role.