Research Scientist - Audio

ABOUT RETELL AI Retell AI is using first principles to reimagine the call center with cutting-edge voice AI. Thousands of companies now utilize Retell’s AI voice agents to handle sales, support, and logistics calls that once required large teams of human agents. Backed by Y Combinator, Alt Capital, and other leading investors, we have scaled to $60M ARR with a team of 40 people, up from $5M at the start of 2025. Our vision for 2026 is to build a modern CX platform where entire contact centers are powered by AI. Instead of basic automation that needs constant human tuning, we’re creating intelligent AI “workers” that can act as frontline agents, QA analysts, and managers, continuously executing, monitoring, and improving customer interactions. We’re growing quickly and looking for ambitious builders who want to tackle hard technical problems, move fast, and have real impact at one of the fastest-growing voice AI startups. Let’s build the future together. - We’re a top 50 AI app in a16z list: https://tinyurl.com/5853dt2x - #4 on Brex's Fast-Growing Software Vendors of 2025: https://www.brex.com/journal/brex-benchmark-december-2025 - We're also one of the top ranking startups on: https://leanaileaderboard.com/ - Enterprise tech 30: https://www.wing.vc/et30/overview ABOUT THE ROLE This is a research-driven, high-impact role for ML researchers who want to push the boundaries of real-time AI. As a Founding Machine Learning Research Engineer at Retell, you’ll focus on advancing model capabilities for human-like voice agents operating in complex, real-world environments. You’ll explore new approaches across LLMs and audio models, design novel evaluation methods, and prototype systems that improve reasoning, latency, and conversational quality. Your work will directly influence production systems, bridging cutting-edge research with real-world deployment. If you’re excited about solving open-ended ML problems, experimenting rapidly, and shaping how voice AI systems think and