Product Engineer (UI / Frontend)

About the Position

Product Engineer (UI / Frontend)

Maincode is building the next version of Matilda, the first large language model built and trained from scratch in Australia. We are now scaling the model and deploying it as a live production system.

To do that, we build AI systems from first principles. We design the architectures, run the infrastructure, shape the training process, and operate the systems that serve our models.

Matilda is a production system, not a research prototype, built to be deployed and served for open public access. If the training stack is how Matilda learns, the product is how people experience it. This role sits directly in that layer.

You will help build the user-facing experience of Matilda. Not just how it is implemented, but how it feels, behaves, and communicates with users. You will contribute to designing and building the interfaces that turn a model into a coherent product.

This is not a pure handoff role. You will work closely on both the UX and the implementation, shaping interactions and details directly in code.

Responsibilities

• Building the core web interface for interacting with Matilda (chat, sessions, history, settings)
• Implementing fast, reliable streaming UX for model outputs (real-time tokens, partial responses, cancellation, retries)
• Contributing to interaction design across common and edge-case flows (latency, uncertainty, refusals, errors)
• Helping design UI workflows that support safe and responsible use (reporting, feedback, content handling)
• Iterating on layout, typography, spacing, and interaction details directly in code
• Improving perceived performance and responsiveness through thoughtful UI decisions
• Building internal tools and dashboards with a strong focus on clarity and usability
• Working closely with backend and infra engineers to integrate APIs, auth, and system constraints

Requirements

• Have strong visual taste and attention to detail (spacing, typography, motion, polish)
• Care about interaction quality and the small details that shape user experience
• Enjoy working across design and engineering rather than staying strictly in one lane
• Think in terms of user flows and states, not just components
• Are comfortable making reasonable UX decisions and iterating quickly
• Have solid engineering fundamentals and write clean, maintainable code
• Are curious, practical, and willing to learn from real usage

Skills

• TypeScript
• Modern front end tooling
• Real-time or streaming interfaces
• UI
• Modern tooling

We Offer

• Opportunity to work on a cutting-edge AI project
• Collaborate with a small, talented team
• Work closely with research, backend, and infrastructure teams

About the Company

Maincode builds AI systems end to end. We prepare the data, design the training process, run the infrastructure, and operate the models ourselves. You will work with a small team that:

• Builds the full AI stack rather than outsourcing it
• Treats product experience as part of the intelligence system itself
• Values taste, creative judgment, and craft
• Is building long-term capability in training, deploying, and operating large models

If you care about building thoughtful, high-quality user experiences and want to work close to the core system, you will be well placed here.

Application Note

We care a lot about what you have actually built.

Please include examples of products, interfaces, or features you have worked on that you are proud of. This can be professional work or personal projects. We are particularly interested in:

• Interfaces where you shaped the UX, not just implemented it
• Work that shows attention to detail and visual craft
• Anything that demonstrates good judgment in interaction or product decisions

This is a full-time role based in Melbourne, working closely with our in-person engineering and research team. At this time, we are not able to offer visa sponsorship, so applicants must have existing and unrestricted work rights in Australia.