Founding Senior Software Engineer (Backend)

Get AI-powered advice on this job and more exclusive features. This range is provided by Retell AI. Your actual pay will be based on your skills and experience - talk with your recruiter to learn more. Base pay range $215,000.00/yr - $290,000.00/yr Additional compensation types Annual Bonus and Stock options Direct message the job poster from Retell AI Co-Founder @ Retell AI | Building the most human-like AI for automating phone calls for businesses. About Retell AI At Retell AI, 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. We're also one of the top ranking startups at . 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 Retell'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. Interview Process Online Assessment (25-30 min) : One HackerRank coding questions on practical problem-solving (7 days to complete). Technical Phone Interview 1 (30 min) : Live coding on CoderPad, focusing on data structures and algorithms. Technical Phone Interview 2 (30-45 min) : Deeper CoderPad session on algorithmic thinking and coding fluency. Onsite/Virtual Interviews (2-3 hrs) : Hosted in our office if located in the Bay Area or virtual, with three rounds: Practical Coding: Tackle real-world coding tasks with debugging in a basic environment set up like Python Flask or Node.js Express, etc. System Design: Architect a production-ready system. Tools & Automation: Build automations or improve workflows in any basic environment setup like Python Flask or Node.js Express, etc. Learn More Retell AI - API That Turns Your LLM Into A Human-Like Voice Agent Retell AI Basics: Everything You Need to Start Building Voice Agents Join Retell AI to build the future of voice automation, shipping impactful code and defining a new standard for AI-driven communication. Seniority level Seniority level Mid-Senior level Employment type Employment type Full-time Job function Industries Technology, Information and Internet Referrals increase your chances of interviewing at Retell AI by 2x Inferred from the description for this job Medical insurance Vision insurance Get notified about new Software Engineer jobs in San Francisco Bay Area . 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