Senior/Staff UXer

⚡ About Supersonik

Supersonik builds an AI sales agent that runs live product demos. The agent enters a real product interface, navigates it in real time, and walks an enterprise buyer through it — interactively, and in multiple languages.

We are around 40 people, with a tech team of seven, offices on Diagonal in Barcelona and a recently opened go-to-market office in New York. We are backed by a16z, and our clients are enterprise SaaS companies including Salesforce, HubSpot, Brevo, Lemlist, Holded and Lodgify. One of our co-founders, Joaquim Lecha, was previously CEO of Typeform.

🎯 About the role

We have built a strong technical team. There are people here whose full attention goes to agent reliability, to platform scalability, to observability, and to applied AI research, and the quality of that work is visible in the product.

Design is the one area without a dedicated owner. It is nobody's speciality today, so improvements to the experience happen occasionally rather than continuously. We are looking for someone whose full attention is on it.

This is the first design hire at Supersonik. You would own the experience of the product end to end, and report to Pol, our CTO.

🛠️ What you'll do

Design the in-demo experience. We control the demo from end to end, which means every part of it is ours to shape: how the layout works, how a buyer understands what the agent is doing, how we communicate that the agent is thinking, and what appears on screen at the moment it helps a demo convert.

Design the platform. This is where agents are configured, where the intelligence extracted from demo calls is presented, and where our dashboards live. Our own go-to-market team is the primary user today; the goal is to make the platform intuitive enough that clients can eventually run it themselves.

Design the agent configuration experience. A significant part of the platform works through a chat: a user describes what they want their agent to do, and an LLM translates that into the real configuration. The visual design problem here is small and the experience problem is substantial. What should the system ask, and in what order? How does it draw out what the user is actually trying to achieve? How do you show someone with no knowledge of prompting what has changed in their agent, and give them reason to trust it?

🔍 What we're looking for

5+ years designing software products. We care more about what you have owned than about the number.

Depth in user experience and product judgment rather than visual craft. Designing a chat interface is not the difficult part; designing the experience of using one is.

A practice that ends in shipped work, not in a handoff. You prototype and implement your own work, using AI tooling where it helps. You do not need to be an engineer, and we are not hiring one.

Autonomy. There is no design team, no design lead and no product manager, and we do not plan to add those layers. Nobody will bring you a backlog.

Direct contact with users. Our go-to-market team is our first user. We expect you to sit with them and gather feedback yourself rather than receive it second-hand.

The confidence to hold and argue a position. In a room of engineers, your judgment on this is the reason you are here.

Nice to have: experience designing products where AI is the interface — chat, agents, non-deterministic behaviour.

✨ What we offer

Above-average salary for the Barcelona design market

Equity stake

Private health insurance and Cobee

Full ownership of the design function from day one

Hybrid with preference for onsite in Barcelona, with the whole team in one place