AI Voice Designer

At Sierra, we’re creating a platform to help businesses build better, more human customer experiences with AI. We are primarily an in-person company based in San Francisco, with growing offices in Atlanta, New York, London, Paris, Madrid, Munich, Singapore, Tokyo, and Sydney. We are guided by a set of values that are at the core of our actions and define our culture: Trust, Customer Obsession, Craftsmanship, Intensity, and Family. These values are the foundation of our work, and we are committed to upholding them in everything we do. Our co-founders are Bret Taylor and Clay Bavor . Bret currently serves as Board Chair of OpenAI. Previously, he was co-CEO of Salesforce (which had acquired the company he founded, Quip) and CTO of Facebook. Bret was also one of Google's earliest product managers and co-creator of Google Maps. Before founding Sierra, Clay spent 18 years at Google, where he most recently led Google Labs. Earlier, he started and led Google’s AR/VR effort, Project Starline, and Google Lens. Before that, Clay led the product and design teams for Google Workspace.

Voice is one of the most demanding and important surfaces for AI agents. How an agent sounds – its warmth, tone, pacing, accent, and personality – is often the first and most lasting impression a customer has of a brand. Getting it right is equal parts craft, taste, and technical execution. We're looking for a technical Voice Designer to own that craft. This is a forward-deployed role: you'll work hand-in-hand with Sierra's customers to develop, build, launch, and continuously improve the voices our agents use across our European locales. You are the person who turns a customer's requirements into a living, production-quality AI voice. You’ll work closely with our voice platform team to implement and tune voices that run at scale on our infrastructure. This will include recording and editing audio, and configuring voices in the Sierra platform (including by making some code-level changes) to bring these voices to life. You’ll partner with the Platform team to build new tools that make voice development increasingly self-serve over time. This is a hands-on role that blends product sensibility, design taste, customer partnership, and enough technical comfort to work directly in command-line tooling. It sits at the intersection of speech, brand, and engineering. What You’ll Do Develop new voices — Design and implement natural-sounding production-ready voices for European locales and key customers, from first concept through launch. Own the end-to-end experience of how a voice sounds—and make deliberate, tasteful choices about accent, pacing, personality, and prosody. Build and tune voices in the tooling — Tune voices directly using Sierra's platform tooling, including running command-line prompts and submitting pull requests. You're comfortable operating in this environment and iterating quickly. Direct and record voice talent — Source, direct, and record voice actors. Cut, clean, and prepare audio files for use in the voice pipeline, ensuring recordings meet the quality bar for synthesis. Partner with customers on requirements — Work directly with Sierra's customers to understand both their hard requirements (locale coverage, latency, telephony constraints, compliance) and soft requirements (brand personality, tone, warmth, register). Translate fuzzy brand language into concrete, buildable voice specifications. Make voice quality measurable — Help define how we judge whether a voice is good: naturalness, brand fit, intelligibility, and consistency across a conversation. Build feedback loops with customers and contractors that improve voices over time. Manage a network of language contractors — Employ and manage contractors with native language skills who can partner with you to tune voices in their languages, review nuances a non-speaker would miss, and assess quality improvements over time. Build