Senior Software Engineer, Backend

Stealth Startup; San Francisco (CA); Hybrid; USD 215,000 - 290,000; Full time

Benefits offered by this job

Unlimited meals

Gym and commute reimbursements

Internet and phone bills covered

Job summary

Stealth Startup in Redwood City, CA, seeks a Founding Senior Backend Engineer to shape core systems powering millions of AI-driven conversations. You’ll own architecture, real-time audio handling, and developer tooling, working with the founding team.

We value ownership, startup grit, and collaboration; 2+ years backend experience and a CS/CE/EE degree are required. This full-time role offers on-site work with flexible hours and remote options, plus visa sponsorship.

Qualifications

• 2+ years of backend development experience.
• Degree in CS, CE, or EE is required.
• Startup experience or grit is a plus.
• Comfort with fast-paced, ambiguity and ownership responsibilities.

Responsibilities

• Build foundational backend architecture and APIs for the platform.
• Design scalable backend systems and DevOps workflows.
• Lead projects from architecture to production and monitor delivery.
• Collaborate with product/design for quick customer onboarding.

Skills

Backend development

DevOps

Cloud infrastructure

Startup experience

Education

CS, CE, or EE degree

Job description

We're not just automating calls—we’re transforming how the world communicates. Our AI voice agents are reshaping sales, support, and customer engagement for leading brands. Backed by Alt Capital, Y Combinator, and top-tier investors, we've raised $4.7M in seed funding and hit $14M ARR with just 12 people.

We’re one of the fastest-growing Voice AI startups and we're on a mission to become the standard for voice automation at scale.

About the Role

As a Founding Senior Backend Engineer, you’ll shape the core systems powering millions of AI-driven conversations. You’ll tackle real-time audio, global telephony, and developer tooling, working across the stack with the founding team. This high-impact role offers rapid feedback loops, customer collaboration, and the chance to define a category-leading product.

Key Responsibilities

• Build foundational architecture for the company's platform, such as prompt orchestration, testing frameworks, observability dashboards, and telephony integrations.
• Design scalable backend systems and DevOps workflows for reliable performance across millions of calls.
• Lead complex projects from architecture to production, driving delivery and monitoring.
• Collaborate with product and design teams to create intuitive APIs and interfaces for quick customer onboarding.
• Support customer onboarding, troubleshoot issues, and turn feedback into product improvements.
• Have 2+ years of backend development experience with a degree in CS, CE, or EE.
• Take ownership like a founder, with a passion for impactful software.
• Thrive in fast-paced, ambiguous environments, solving new problems with curiosity.
• Communicate clearly, collaborate across teams, and drive momentum.
• Have startup experience or grit to adapt, with bonus points for cloud infra/DevOps knowledge.
• Job Type: Full-time, 70 hr/week (50 hr/week onsite with flexible hours + 20 hr/week work from home)
• Cash: 215k - 290k
• Equity: 0.4 - 0.6%
• Location: Redwood City, CA, US
• US Visas: Sponsors Visa & Green Card

Other Benefits

• Unlimited breakfast, lunch, dinner, and snacks
• Gym and daily commute fee reimbursement
• Internet and phone bills covered

Compensation Philosophy

• Best Offer Upfront: Choose from three cash-equity balance options, no negotiation needed.
• Top 1% Talent: Above-market pay (top 5 percentile) to attract high performers.
• High Ownership: Small teams, >$1M revenue/employee, and significant equity.
• Performance-Based: Offers tied to interview performance, not experience or past salaries.