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Fullstack Engineer

Phonic

Phonic

Software Engineering
San Francisco, CA, USA
Posted on Mar 6, 2026

Location

San Francisco

Employment Type

Full time

Location Type

On-site

Department

Engineering

About Phonic

Phonic is a product and research lab focused on powering the most realistic, human-like voice AI conversations. We've re-thought the entire stack in pursuit of this goal, from models to product, to create voice agents that feel like they truly understand you, respond emotionally and perform agentic tasks with frontier intelligence.

Our team includes top-tier AI researchers, international olympiad medalists, and former founders.

Our customers include companies that are building voice-native AI products in industries such as customer support, healthcare, and logistics. We have raised over $30M from First Round and Lux Capital.

About the Team

Phonic has a very talent-dense and close-knit team. We collaborate with high trust and are constantly trying to improve how we work to deliver world-class research and product. Everyone takes ownership in what they do and they aren’t afraid to dive in headfirst into new problems. Our team includes top-tier AI researchers, international olympiad medalists, and former founders and we’re fully in-person in our SF office.

The Role

As a Fullstack Engineer at Phonic, you'll build the product layer that brings our voice AI to life for customers. From the real-time interfaces that power live voice conversations to the dashboards, APIs, and developer tooling that our customers rely on daily - you'll own the full surface area of what users see and interact with.

You'll work in close collaboration with our research and ML teams to translate cutting-edge voice AI capabilities into polished, production-grade product experiences. This is a role for a builder who cares deeply about craft, moves fast, and isn't afraid to take end-to-end ownership of features from design to deployment. You'll be fully in-person in our SF office.

What You’ll Do

  • Own features end-to-end in our TypeScript and React codebase, from ideation to launch, while holding a high bar for UX and design quality

  • Build scalable full-stack systems, polished UIs, robust developer-facing APIs, and the SDK layer that ties them together

  • Work closely with research and model engineering to shape how our voice AI capabilities are experienced in product

  • Contribute across the entire stack to ensure seamlessness between our UI, SDK, and platform

What You’ll Bring

  • You've built and shipped beautiful products before and can point to work you're proud of

  • You care deeply about design and UX, you have strong taste and the confidence to defend it

  • You set direction, own decisions, and get things across the finish line; shipping is a skill!

  • You're comfortable across the full stack: frontend, backend, APIs, and everything in between

  • You thrive where you can be autonomous, opinionated, and move fast

Nice To Have

  • Experience building real-time or streaming applications, WebSockets, WebRTC, or audio/media APIs

  • Familiarity with voice, telephony, or conversational AI products

  • You are a former product lead or founder

Benefits

  • 💸 Top-tier compensation: in order to get the best talent, we provide salary and equity that recognize your skillset

  • 🥗 Meals: free breakfast, lunch, and dinner provided in the office

  • 🩺 Healthcare: Comprehensive health, dental, and vision

  • 🤝 We have regular off-sites and team celebrations

  • 👵 401(k) – Let us help you plan for the future. We’ve got you covered.