Frontend Intern: Design the Interface That Makes AI Findings Clear

Salary Unpaid

Turn complex pay errors into something anyone can act on.

Our AI finds pay errors in seconds. But a finding is only worth something if a union case handler understands it right away and can act on it. That is where you come in. As our frontend intern, you will shape how people see, trust and use what our AI finds.

About PayTjek

PayTjek checks payslips and employment contracts against Danish collective agreements. We combine the latest within AI and machine learning with a deterministic rule engine, so every error comes with a reference to the exact clause in the collective agreement. Our customers are trade unions, and the system checks 12 payslips in 90 seconds.

Korrekthed. Ikke sandsynlighed. Correctness, not probability.

We are a startup with big ambitions. Our goal is to make payslip checks a natural part of what every trade union offers its members, first in Denmark and then across Europe.

What you will work on

The case handler's workspace, where errors from our AI and rule engine are collected in a case flow
The member app, where people upload their payslip and follow their case
Turning legally complex results into clear, trustworthy interfaces
Making design choices on layout, hierarchy and flow, and being able to explain why
Testing with real users and improving based on what you learn

Who you are

You have a real eye for UI and UX, and you care about why a design works, not just how it looks
You have experience with a modern frontend framework, such as React and TypeScript
You can take a design from idea to working code
Python or experience with AI products is a plus
Most important of all: you are eager to learn and take ownership
You are able to work from our office in central Copenhagen

What we offer

Hands-on work with the newest technology within AI and machine learning
Real influence on how a product used by real customers looks and feels
Daily sparring and learning from a high-quality team
A real opportunity of employment after the internship, just like our first full-time developer

This is an unpaid internship. It can be done as part of your studies with ECTS credits, if your programme allows it.

How to apply: Apply here on The Hub with a short motivation, your CV and your portfolio. Show us a design decision you are proud of, and tell us why you made it.

Questions? Feel free to call me, Theis Veddinge, Co-founder and CEO, on +45 61 54 19 23.

For more information or questions please contact us at theis@paytjek.io or phone number +45 61 54 19 23

Perks and benefits

This job comes with several perks and benefits

Near public transit

Remote work allowed

Central office

Free coffee / tea

Skill development

Flexible working hours

Working at
PayTjek

See company profile

PayTjek verifies payslips and employment contracts against Danish collective agreements, with a level of certainty that probabilistic AI cannot offer. Korrekthed. Ikke sandsynlighed. Correctness, not probability. The problem Pay errors are widespread, yet very few payslips ever get checked. Collective agreements are complex, and checking payslips by hand is slow work for trained case handlers. As a result, trade unions only reach a small fraction of the payslips where errors hide, and members lose money they are owed. Our solution PayTjek is an internal tool for trade unions. We combine the latest within AI and machine learning with a deterministic rule engine: AI reads documents and extracts the rules from collective agreements, and the rule engine validates every rule and every calculation. Members upload their payslip through an app. The case handler works in a case flow where every error comes with a direct reference to the relevant clause in the collective agreement and a plain explanation, so the case handler can act right away and has the documentation ready to raise the claim. Member and union can follow up with each other directly in the flow. This lets trade unions offer payslip checks as a natural part of their membership offering, at a scale that was not possible before, without adding pressure on their resources. Our ambition We are a young company with big ambitions. We start with Danish trade unions and the Danish labour market, and our goal is to make payslip verification a standard part of what unions offer their members across Europe. PayTjek was founded in Copenhagen in 2025 by Theis Thøger Veddinge and Anton Gammelmark Andersson, with roots in research on formal verification, and is supported by Innovationsfonden.