Senior Frontend Developer
Senior Frontend Developer
Amsterdam
Introduction
As a Senior Frontend Developer, you’ll work on one of the most complex browser-based environments out there: a visual modelling platform where users design entire applications through flowcharts, data models, and UI components.
You won’t be working with standard frameworks like React or Vue. Instead, you’ll contribute to a custom-built MVVM reactive framework in TypeScript. This role is perfect for engineers who deeply understand how frontend frameworks work under the hood and want to push the boundaries of what’s possible in the browser.
Learn more about the company
About the company
Revolutionize your business operations by building custom enterprise no-code software with orchestrated agentic AI. WEM lets you build and scale intelligent applications with AI process automation, driving breakthrough outcomes at incredible speed.
About the role
Benefits
- Salary range of €4,500 to €6,500 per month
- STAK equity scheme (available after the first year for high-performing employees)
- Work on a highly complex, non-CRUD frontend platform
- Build and shape a custom frontend framework
- High ownership and direct impact on product decisions
- Flat engineering culture with no unnecessary processes
- Small, senior engineering team (±15 engineers)
- Fast iteration cycles and real influence on architecture
- Exposure to AI-driven product development
Required Skills
- Deep expertise in TypeScript (advanced types, generics, type safety)
- Strong understanding of reactive systems and state management
- Solid knowledge of the DOM and browser internals
- Strong CSS / SCSS skills (layout, performance, responsiveness)
- Experience with complex UI architectures
- Understanding of algorithms and data structures in a frontend context
- Experience with async patterns and event-driven systems
- Familiarity with REST APIs, JSON, and authentication flows (OAuth 2.0)
- Ability to think beyond frameworks and understand underlying principles
- Proactive mindset with strong ownership
- Fluent in English
- EU work authorization required
Key Responsibilities
- Build and evolve the core visual modelling UI of the platform
- Work within and contribute to a custom MVVM reactive framework
- Solve complex frontend challenges such as drag-and-drop, canvas rendering, and real-time updates
- Optimize performance for large-scale data interactions in the browser
- Collaborate closely with backend engineers on APIs and data flows
- Contribute to frontend architecture and technical direction
- Improve scalability and maintainability of the UI codebase
- Think critically about trade-offs in performance and user experience
Solve Real Frontend Challenges
Go far beyond standard CRUD applications and work on highly complex UI problems that push the limits of the browser.
Build Instead of Consume
Contribute to a custom-built frontend framework and shape how it evolves, rather than relying on off-the-shelf tools.
High Ownership & Impact
Work in a small, senior team where your decisions directly influence the product and technical direction.
Application process
Let us know you’re interested by applying for this role!
Get to know each other and learn more about our company.
Complete a short task or skills test relevant to the position.
A follow-up with senior team members or decision-makers.
You’ll receive a formal offer with all the details.
Office locations
Revolutionize your business operations by building custom enterprise no-code software with orchestrated agentic AI. WEM lets you build and scale intelligent applications with AI process automation, driving breakthrough outcomes at incredible speed.
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