Backend Developer

Lumina; København; On-site; DKK 650,000 - 950,000; Full time

Job summary

Lumilab, Copenhagen based, is seeking an exceptional backend developer to build and scale the platform that lets operators deploy their own agents. You’ll own features from architecture to production, design robust APIs, data models and ensure reliability as usage grows.

You’ll work in a lean team, collaborating closely with founders and customers, taking ownership of substantial parts of the system, and contributing to architectural decisions. We offer a competitive base salary and equity.

Qualifications

• Experience building production backend systems in a startup or scale-up.
• Proven ability to own features end-to-end from design to production.
• Strong backend fundamentals, APIs, data models and performance considerations.

Responsibilities

• Design, develop and scale the backend platform for deploying agents.
• Extend deployment framework with monitoring, reporting and workflows.
• Develop APIs, data models and integrations to support new features.
• Improve scheduling and reliability as usage grows.
• Write clean, performant code and ship features to production.

Skills

Backend fundamentals

End-to-end ownership

System design

Independent work

AI coding tools

Tools

AI coding tools

Job description

TL;DR

In office - Copenhagen based. Not a remote position. At Lumilab, we’re building a lean team of top performers. We’re looking for an exceptional backend developer to continuously develop and scale the platform that lets operators deploy their own agents. You’ll design, ship and own new features and system, from architectural decisions to how they perform in production.

You bring high agency, strong engineering judgement and a track record of delivering results independently. You take full ownership of what you build and expect the same standard from your teammates.

Why Lumilab?

We’re building Agentic Operations for the physical world. Our vision is that the next billion distributed assets in the physical world will be operated by teams orchestrating AI agents. Lumilab is building the layer that makes that possible.

Since launching 12 months ago, we’ve gained customers across eight countries. Last month alone, usage of our software grew by 56%.

That growth brings engineering challenges: running more agents, handling more data and making increasingly complex workflows reliable. You’ll help build the next version of our platform, giving operators the tools to configure and deploy agents for monitoring, reporting and operational tasks.

Joining now means having a direct say in our architecture, engineering practices and product. You’ll work close to the founders and customers, see your work used in real operations and own substantial parts of the system.

We offer a competitive base salary and equity, reflecting the responsibility you take and the company you help build.

Who We’re Looking For

We’re building a lean team of exceptional developers, and we’re deliberate about keeping the bar high. Every person needs to deliver strong results, work independently and take full ownership of what they build. We’re looking for top performers who want that level of responsibility and expect the same standard from their teammates.

• You’ve owned products or systems end-to-end. You’ve built and operated production software in a startup or scale-up, or taken comparable responsibility elsewhere. You can explain the decisions you made, the trade-offs involved and what happened after launch.


• You have high agency. You identify what needs doing, bring ideas and act on them. You’re comfortable turning an unclear problem into a concrete plan with minimal direction.


• You move quickly with high standards. You have strong backend fundamentals, write maintainable, performant software and make deliberate trade-offs. You finish work and check that it solves the problem.


• You learn fast and adapt. You can get to grips with unfamiliar systems, investigate problems methodically and change course when the evidence calls for it. You’re willing to experiment, get things wrong and learn from feedback.


• You build with AI as your default. You use AI coding tools throughout development and expect them to generate most of your code. You understand, review and test what they produce, and take full responsibility for the result.

What You’ll Do

Design, develop and scale the backend platform that allows operators to configure, deploy and run their own agents.

• Extend and improve our agent deployment framework with new capabilities for monitoring agents, automated reports and operational workflows.


• Develop and evolve APIs, data models and integrations to support new features and agent capabilities.


• Improve scheduling, execution and failure recovery so the platform stays reliable as usage and complexity grow.


• Write clean, performant code and understand its behavior throughout the product, from API requests and database queries to agent execution in the runtime.


• Take features from problem definition to production, working with the team and customers to understand their impact and improve them after launch.

How We Work

We’re building a lean team where each person owns meaningful parts of the product. We agree on goals and interfaces, then give people the autonomy to deliver. We design our systems and divide work so that teammates can ship independently, with few dependencies slowing them down.

Ownership includes understanding the problem, choosing an approach, implementing it and making sure it works in production. We communicate decisions early, ask for input when it is needed and follow through.

We believe the best argument wins. Everyone’s perspective has value, and we expect people to listen carefully, challenge ideas openly and update their views when someone makes a stronger case.

We keep exploring new tools and approaches, adopting them when they help us build better software or deliver faster.