Senior Software Engineer (Backend-focused, Full Stack)

LeanLinking ApS; Denmark; On-site; DKK 900,000 - 1,200,000; Full time

Benefits offered by this job

Competitive salary

Professional development

Great lunch

Job summary

LeanLinking ApS, a small, dynamic SaaS company, seeks a Senior Software Engineer to own backend development with strong frontend capabilities in React TypeScript. You will write code daily, influence architecture, and mentor teammates while integrating AI and LLM tools into daily workflows.

You’ll collaborate with the .NET Core backend and React TypeScript frontend, build robust solutions, and help shape how AI is used across the product and development process.

Qualifications

• Strong experience with .NET Core and React TypeScript (or similar).
• Solid understanding of both frontend and backend development.
• Hands-on experience using AI coding assistants in real projects.
• Bonus: experience setting up project-level AI context files.
• Fluency in written and spoken English.

Responsibilities

• Develop and maintain features across the entire stack, with a focus on the backend.
• Use AI coding assistants as a normal part of daily workflow for scaffolding, refactoring, and tests.
• Use AI services to build smarter product workflows faster.
• Help maintain and evolve project context files to keep AI tools grounded in codebase conventions.
• Prototype and test new AI/LLM-driven concepts and features.
• Collaborate on technical and architectural decisions.
• Participate in client meetings to evaluate and scope requests.
• Mentor and spar with other developers, sharing knowledge and experience.

Skills

.NET Core

React TypeScript

Full-stack development

Mentoring

English communication

Tools

Claude Code

GitHub Copilot

Cursor

Codex

Job description

Help shape the future of procurement solutions for global enterprises!

Who we are

We’re a small, dynamic SaaS company that provides cutting-edge tools for procurement teams in global enterprises. With a strong focus on innovation, we work with technologies like .NET Core and React TypeScript and we're actively integrating AI and LLMs into both our product and our own development workflow. Our team is young, vibrant, international and balanced. Our office is based in Aarhus N (close to Ikea) where we enjoy working together in person.

The role

We're looking for a Senior Software Engineer who’s passionate about Backend development but is also capable of contributing across the stack (Frontend – ReactJS Typescript). You will be hands‑on, writing code daily, but you'll also influence technical and architectural decisions and support our team with code reviews, sparring and mentoring.

You’ll work closely with our .NET Core backend and React TypeScript frontend, building robust and scalable solutions — increasingly with AI coding tools as part of the daily loop, not as an afterthought. As we expand our own use of AI and LLMs, you'll help shape how the team builds with them.

What you’ll do

• Develop and maintain features across the entire stack, with a focus on the backend
• Use AI coding assistants (e.g. Claude Code, GitHub Copilot, Cursor, Codex) as a normal part of your daily workflow — for scaffolding, refactoring, test generation, and code review
• Use AI services to build smarter product workflows faster
• Help maintain and evolve our project context files (e.g. CLAUDE.md / AGENTS.md-style setups) so AI tools stay useful as the codebase grows
• Prototype and test new concepts and features, including AI/LLM‑driven ones
• Collaborate with the team on technical and architectural decisions
• Participate in client meetings to evaluate and scope client requests
• Mentor and spar with other developers, sharing their and your knowledge and experience

Your profile

• Strong experience with .NET Core and React TypeScript (or similar technologies)
• Solid understanding of both frontend and backend development
• Practical, hands‑on experience using AI coding assistants (Claude Code, Copilot, Cursor, Codex, or similar) in real projects — you know their strengths, their failure modes, and how to review their output critically rather than accepting it blindly
• Bonus: experience setting up or maintaining project‑level AI context files (CLAUDE.md, AGENTS.md, .cursor rules, or equivalent) to keep AI tools grounded in your codebase’s conventions
• A passion for best practices and modern development tools and methodologies
• Ability to contribute to technical decisions and work closely with others on the team
• Willing to mentor and support the growth of more junior developers
• Hands‑on, proactive, and keen to take ownership of projects
• Good business sense
• Fluency in written and spoken English

What success looks like

• Your contribution to and creation of solutions and features that impress our customers
• Your contribution to ensuring our tech stack is constantly modern and state‑of‑the‑art
• Your contribution to a great team work with a winning attitude

What we offer

• A young and diverse team with a supportive culture
• Competitive salary and benefits
• Great opportunities for professional development and career advancement
• Various employee benefits including great lunch