Senior Full Stack Engineer
– Build, Scale, and Shape the Future of Predictive AI –

At Neurons, we’re revolutionizing how brands understand and engage with people. By combining state-of-the-art AI with deep neuroscience insights, we enable companies to predict consumer responses in seconds; transforming marketing into something truly predictive and actionable.

We’re looking for a Senior Full Stack Engineer to help us push this mission forward. This isn’t a role about ticking boxes; it’s about building systems that scale, shipping products that deliver impact, and raising the engineering bar as we grow.

You’ll join our newly established API & Integrations team, whose goal is to enable customers and partners to interact more closely with the Neurons platform through customer-built integrations, as well as ready-made integrations with major partners in the marketing and advertising ecosystem.

If you’re passionate about designing great technology and seeing it make a difference in the real world, you’ll thrive here.

What You'll Be Driving

Build & Scale Customer-Facing APIs and Integrations
You’ll design and build the APIs that power customer integrations and partner use cases; making them fast, secure, reliable, and scalable. You’ll help define and deliver capabilities like authentication, rate limiting, webhooks/event delivery, versioning, and strong developer experience patterns.

• What helps you succeed: Deep experience with Python (ideally Django or FastAPI), designing production APIs, and working with scalable systems.

Deliver End-to-End Integration Experiences
You’ll work across backend and frontend to ship integration products end-to-end, from API endpoints and data contracts to integration setup flows, onboarding UX, and customer-facing configuration surfaces.

• What helps you succeed: Strong skills in React and TypeScript, plus experience delivering full-stack features from concept to deployment.

Make Our Platform Easy to Integrate With
You’ll improve the developer experience of our platform by shaping documentation and discoverability, enabling better observability, and building tooling that helps customers integrate smoothly (e.g., sandbox environments, API docs improvements, example apps, SDK patterns, or integration testing utilities).

• What helps you succeed: A mindset of building for external developers, and familiarity with API lifecycle best practices.

Ensure Reliability, Quality, and Clean Code
You’ll drive engineering excellence through clean, maintainable code, robust testing, and thoughtful architecture. You’ll ensure integrations remain stable as we evolve the platform.

• What helps you succeed: A track record of building reliable systems with strong testing strategies (unit, integration, end-to-end), and familiarity with principles like SOLID, TDD, or BDD.

Shape Technical Direction With Your Expertise
As a senior engineer, you’ll collaborate closely with product and stakeholders to shape integration strategy and technical decisions. You’ll balance ideal architecture with practical business needs; always aiming to deliver maximum impact.

• What helps you succeed: Experience making architectural decisions (ADRs/RFCs), aligning technical work with business goals, and communicating tradeoffs clearly.

Mentor and Multiply Your Impact
You’ll help build a strong, collaborative engineering culture; mentoring others, leading by example in code reviews, and sharing best practices.

• What helps you succeed: Comfort leading technical discussions, guiding peers, and raising the bar for engineering quality.

What Success Looks Like

• Our APIs scale smoothly as customer usage grows.

• Customers and partners can integrate quickly, with clear workflows and minimal friction.

• Key integration capabilities (auth, webhooks, observability, versioning) are robust and well-designed.

• New product capabilities are shipped rapidly and exposed cleanly through the API and UI.

• Codebases become cleaner, more maintainable, and easier to extend.

• Your technical leadership makes the entire team stronger and more effective.

The Experience That Helps You Succeed

While there’s no single “perfect” background, we think the ideal candidate will bring most of the following:

• ~5+ years of professional experience building and scaling web applications.

• Proven expertise with Python (Django or FastAPI) and designing production-ready APIs.

• Strong skills with TypeScript, React, and modern frontend architecture (React Query experience is a plus).

• Hands-on experience with distributed systems, asynchronous programming, and message queues.

• Experience building integration-friendly systems (e.g., API versioning, auth strategies such as OAuth/JWT, webhooks, rate limiting, observability).

• A history of delivering robust testing strategies and maintaining production-grade codebases.

• Strong communication skills and a collaborative mindset: you thrive in cross-functional, Agile teams.

Shape What's Next With Us

• Work on technology that merges AI, neuroscience, and marketing - solving problems no one else is tackling.

• Tackle complex engineering challenges with a team that values creativity, collaboration, and craftsmanship.

• See your work deliver measurable impact for some of the world’s biggest brands.

Location: This role is based at our headquarters in the Greater Copenhagen Area. (We’re unable to support fully remote work for this position.)

Join the Neurons Movement!

In our inclusive culture, innovation flourishes. We believe true progress comes from being yourself, sharing ideas freely, and collaborating with inspiring colleagues. So if you're all about the above, come help us redefine consumer neuroscience!

Innovation at our Core: Our 11-year legacy began with neuroscientist and bestselling author, Dr. Thomas Zoëga Ramsøy, a leading figure in the fields of applied neuroscience, consumer neuroscience, and neuromarketing. Innovation continues to drive everything we do, from our CEO to each and every team member, we push boundaries and foster forward-thinking, leveraging data and AI to transform our industry.

Team Spirit and Culture: We’re committed to fostering a culture that values teamwork and personal growth. Building something extraordinary requires effective collaboration and top talent. So why not surround yourself with a supportive team that drives success!

Results with Empathy: We’re focused on achieving results while also prioritizing empathy. Join a culture that balances ambition with consideration and where continuous feedback on performance and development is encouraged. Here, success is measured not just in numbers, but in relationships, collaboration, and positive impact.

Diverse and Inclusive: Our team of 85 talents from 30 nations proudly celebrates diversity. By embracing diversity and individual development, we believe that we can achieve sustainable growth and remain committed to fostering a culture where people of all backgrounds feel welcomed.

At Neurons, the journey is as exciting as the destination. Experience a career where innovation, teamwork, and meaningful results come together in ways you've never imagined!

We Offer An Array of Benefits

We are a company that takes pride in the health & well-being of all our employees, with initiatives such as yoga practice, healthy breaks, and mental health resources.

We enjoy coming together for our Friday Hygge, where you might find us singing karaoke, playing bingo, video games or board games.

Other benefits include:

• In-house lunch

• Pension plan

• Private health insurance

• Parental leave benefits

• Quarterly company events

• Team events