Frontend Engineer

Hark; San Jose (CA); On-site; USD 170,000 - 400,000; Full time

Job summary

Hark is searching for a frontend engineer to create and enhance user interfaces for advanced AI interactions. In this role, you will build web and mobile interfaces that feel instant and coherent. Your work will be essential in defining how users interact with Hark's technology.

The ideal candidate has 5+ years of experience in frontend engineering, particularly with modern React, and will be responsible for ensuring that Hark's interface is both responsive and trusted by users.

Qualifications

• Deep frontend expertise with modern React or equivalent.
• Experience with streaming data and real-time UI.
• A sharp eye for animation and loading states.
• Shipping products that users depend on.
• Curiosity about LLM-powered products and UX.
• Comfort with prototyping and quick iterations.
• Strong communication skills with designers and engineers.

Responsibilities

• Build and own the frontend surfaces of Hark.
• Ship UI for real-time, streaming agent interactions.
• Collaborate with designers to create fast, responsive interfaces.
• Build accessible components that scale across products.
• Track performance and improve based on user data.
• Work with platform engineers on APIs and data contracts.

Skills

Modern React or equivalent

Real-time UI experience

Attention to detail in UI

Shipping consumer products

Curiosity about AI

Fast iteration

Strong communication

5+ years frontend engineering experience

Job description

About Hark

Hark is an artificial intelligence company building advanced, personalized intelligence. One that is proactive, multimodal, and capable of interacting with the world through speech, text, vision, and persistent memory.

We're pairing that intelligence with next-generation hardware to create a universal interface between humans and machines. While today's AI largely operates through chat boxes and decade-old devices, Hark is focused on what comes next: agentic systems that interact naturally with people and the real world.

To get there, we're developing multimodal models and next-generation AI hardware together - designed from the ground up as a single, unified interface for a new era of intelligent systems.

About the Team

You’ll own the frontend experience of Hark: the interfaces people see, touch, and talk to every day.

That means building UI that keeps up with a real-time, streaming AI agent. Interactions that feel instant. State that stays coherent across voice, text, and vision. The kind of polish that makes people trust what they're using.

This is a high-ownership role on a small team. You'll work directly with designers and the engineers building the agent platform, and what you ship will define how Hark feels to use.

Responsibilities

• Build and own the frontend surfaces of Hark: web, mobile web, and the component systems that power them.
• Ship UI for real-time, streaming agent interactions. Handle partial responses, tool invocations mid-stream, and state updates that arrive out of order.
• Work closely with designers to translate vision into interfaces that feel fast, responsive, and trustworthy. Sweat the details.
• Build accessible, performant components that scale across Hark's product surfaces.
• Instrument what you ship. Track performance, catch regressions, and improve based on real usage data.
• Collaborate with platform engineers on the APIs and data contracts that connect the frontend to the agent runtime.

Requirements

• Deep frontend expertise. You know modern React (or equivalent), state management patterns, and how to build interfaces that feel great at 60fps.
• Experience with real-time UI. Streaming data, websockets, optimistic updates: you've built interfaces where latency and state consistency really matter.
• A sharp eye for polish. You notice when animations are off, when loading states feel wrong, when something just doesn't feel right, and you fix it.
• Experience shipping consumer products that real people depend on. You understand the gap between a prototype and something someone trusts every day.
• Genuine curiosity about AI and agents. You've used LLM-powered products, noticed where the UX breaks down, and thought about what would make it better.
• Comfort with ambiguity and fast iteration. You can take a rough idea, prototype it quickly, get feedback, and converge on something that works.
• Strong communication. You can partner closely with designers and backend engineers, explain your thinking, and make good decisions together.
• 5+ years of frontend engineering experience. Experience at a fast-growing AI or consumer product company is a strong plus.

Bonus Qualifications

• Experience at a fast-growing AI or consumer product company.
• Experience with voice interfaces.
• Experience with multimodal interactions.
• Experience with mobile development.
• Experience with animation or motion design systems.

Compensation

The US base salary range for this full-time position is between $170,000 - $400,000 annually.

The pay offered for this position may vary based on several individual factors, including job-related knowledge, skills, and experience. The total compensation package may also include additional components and benefits depending on the specific role. This information will be shared if an employment offer is extended.