Product Engineer

Conditions

• Type: Full-time (paid 100% during the trial period as well)

• Location: 96 Muhak-ro 49-gil, Dongdaemun-gu, Seoul (6 min walk from Sinseol-dong Station)

• Schedule: Five days a week on site, flexible start between 9 and 10am

• Compensation: Base salary from KRW 36M. Above that is negotiable based on ability. Performance bonuses or stock options are separate.

• Benefits: Meals covered in full, top-tier AI subscriptions covered in full, flexible hours, budget for books and courses, holiday bonuses and more

We averaged 62% month-over-month growth in the first half of 2026, and more than 10,000 businesses have signed up. We reached that in the seven months since launch. Thanks to the people who believed in that growth, we have also raised over KRW 500M from institutional investors.

The problem we are solving

Selling online is hard. You need a thumbnail to earn the click, a banner to run ads, a short-form video to be seen at all. Selling one product properly means the pile of content you have to make keeps growing.

Making all of it takes a designer, and a designer takes money and time. Well-funded companies can absorb that. Most manufacturers, brands and distributors cannot. So good products end up badly sold.

The time a seller should be spending goes into making a better product and talking to customers. In practice, a whole day disappears into designing marketing assets. We want to remove the repetitive work wedged in between, so everyone can focus on the core of their business. Creazy is the product that removes the content design bottleneck.

Creazy

Creazy started with product detail page design. Today it is becoming a design agent that produces the full range of marketing content online selling requires, including thumbnails, banners and short-form video.

Upload product information and photos, and it plans the selling points on its own and produces a design optimised for the product category. You can edit the result directly in the web editor or hand the edits to the AI in chat, and export as images, Figma files or a web page. What used to take a person all day now takes three minutes.

Where we are

• Over 10,000 online distributors have signed up.

• We averaged 62% month-over-month growth in the first half of 2026.

• We have raised KRW 500M to date.

Building on design, our goal is an AI-native commerce builder that optimises and automates the entire online commerce workflow, through sourcing and distribution, and becomes the next generation Shopify.

Why this role exists

"We got here by building fast, and we did it well. But they say the god of success hides in the details. Now we need someone to make it right."

The thing we have done best so far is build fast and ship fast. As a result we have plenty of features.

The next part is the problem. Having a feature and having that feature sit in front of the user in its best possible form are two different things. Where the button sits, the one line of guidance, the empty screen a user faces when something fails. All of it decides whether they keep their subscription.

This role owns that. We are not looking for an engineer who implements tickets, but for someone who finds what needs fixing, builds it, and ships it. The team is about five people, so there is no handing specs back and forth. Whoever finds the bottleneck is the person who fixes it.

What you will do

1. Advance the Creazy design agent (your first project)

Creazy generates designs through several AI agents that divide the work between them. Your first job is refining that structure to raise the quality of the output. You get to apply the fastest-moving agent design techniques, such as subagents, skills, loops and MCP, to a product that already generates revenue.

Quality here is not abstract. Whether the spacing in a generated design holds, whether generated media stays consistent, whether the system reads a vague instruction correctly and acts on it. You judge these things on the user's behalf, and an eye for detail is the skill that matters.

2. Build the Creazy product

Creazy runs on Next.js and PostgreSQL (Supabase). We do not split front end and back end; you build wherever it is needed. The web editor, the generation pipeline, the subscription and credit system are all in scope.

3. Reduce churn with customer data

You look at user behaviour data, support history and drop-off points yourself and set the priorities. Every week you read the data and act to bring churn down.

4. Improve a business model that already works

You own the billing structure where subscriptions and credits meet. You design and improve the user flows that drive revenue directly: the moment a user out of free credits decides to pay, how to deliver the wow moment sooner, how onboarding and rewards fit together. You work with marketing to widen the funnel from traffic to conversion.

How we work

There are no specs

Whoever notices something proposes it, and once we agree, that person builds it. Almost no time is spent waiting for approval.

We treat AI as a colleague, not a tool

That is why we cover top-tier AI subscriptions in full. We consider ourselves an AI-native team and get our highest productivity working alongside AI.

We think customer-first and obsess over the last 10%

As AI improves, 80% products have become common. What users choose now is the 95% product AI cannot produce in one click. There is no perfect product, but there are careful ones. We design for the sliver of quality users can feel.

What you will have after joining

• After 3 months: You understand the whole agent architecture and have visibly raised output quality with your own hands.

• After 6 months: You decide for yourself what to fix first, and you have moved real user metrics and revenue with that judgement.

• After a year: You have designed and operated an advanced multi-agent product end to end.

What we look for

• You have built a project end to end and put it in front of real users.

• You break down your own work, decide the order, and carry it to the deadline.

• You already use AI tools as part of your daily workflow, or you are eager to.

• Before writing code you ask "if I were the user, what would I do here?"

• You believe one improvement shipped this week beats one polished spec.

We do not look at years of experience. We do need a portfolio, because how you prove the points above is our only criterion. It does not have to be work you did at a company. A side project you built and deployed, a repository, a service you have run all count.

Nice to have

• You have designed AI agents yourself, or built and connected an MCP server.

• You have improved prompts through experiments and measurement rather than intuition.

• You understand online sellers or the e-commerce domain.

• You can read and work in Figma, and speak the same language as designers.

• You have built systems where money moves, such as payments, subscriptions and settlement.

• You have run a service you built and handled user enquiries yourself.

Stack

• Languages: TypeScript (90%), Python (10%)

• Front end: React, Next.js, Tailwind CSS, Zustand

• Back end and data: Node.js, PostgreSQL, Supabase, Redis

• Infrastructure: Vercel, AWS, Cloudflare, Supabase, in-house local servers

Hiring process

Application → On-site interview → Offer discussion → 2-week team fit trial → 3-month probation → Full-time

1. Application: Send a resume and a portfolio together. We cannot review without a portfolio. A repository link, a service you built, slides, an intro deck, anything works.

2. On-site interview: Held at our office with everyone you would work with. We explain what problem we are solving and how, first. Ask us anything.

3. Offer discussion: We share the interview result and talk terms together.

4. 2-week team fit trial: We do not think a few hours of conversation tells either side much. So we work together for two weeks. You are paid 100% for this period.

5. 3-month probation: If both sides are happy after two weeks, we continue for three months. You are paid 100% for this period too. We decide together what you will own during this time.

6. Full-time: If there are no disqualifying issues after the three-month probation, you convert to a full-time role.

How to apply

Use the apply button above and send your resume together with your portfolio. For questions, reach us at contact@thermit.io.