Job Application for Frontend Engineer (Performance & UI Rendering) at arsys ES

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Mission:

Transform Nextcloud Office into a high-performance, modern web-based productivity suite, going beyond traditional DOM-driven applications. You will own the look and feel of the product, ensuring that even the most complex documents and spreadsheets remain fast, smooth, and responsive under heavy load.

Responsibilities:

Build new frontend features such as advanced charts, conditional formatting, and interactive document elements
Develop fast, responsive user interfaces using modern JavaScript
Ensure a smooth 60fps experience across all user interactions (scrolling, typing, zooming)
Move performance-critical rendering logic from the DOM to Canvas or hardware-accelerated technologies
Refactor legacy styles into a modern, performance-optimized CSS system based on variables (supporting dark mode and high-contrast themes)
Implement responsive UI patterns such as optimistic UI to improve perceived performance
Collaborate with other teams to optimize latency and real-time user experience
Leverage AI tools to accelerate development while focusing on performance, edge cases, and UI quality

Requirements:

Technical

Strong experience with modern JavaScript (ESNext)
Deep understanding of DOM behavior and performance trade-offs
Experience with Canvas API or rendering libraries (e.g., PixiJS or Fabric.js)
Solid knowledge of frontend performance optimization techniques
Experience using Web Workers to offload work from the main thread
Experience with modern CSS and performance-oriented styling

AI & Development

Experience using AI-assisted development tools (e.g., Cursor or similar)
Ability to use AI as a productivity multiplier without compromising code quality

Profile

Strong focus on smooth UI and rendering performance (60fps mindset)
High level of English proficiency, with strong communication skills in an international team environment
Attention to detail in user experience and visual quality
Background in demanding frontend environments (e.g., interactive apps, data visualization, or graphics-heavy web applications)
Pragmatic, execution-focused mindset

What We Offer:

Hybrid work model (with preference for our offices in Alcobendas, Valencia, Barcelona, Sevilla, or Logroño)
Flexible working hours
Flexible compensation package
Discounts on Arsys products
Discounts on technology brands
Personalized training and development plans
Biannual team events
Access to advanced AI tools with no usage restrictions
Challenging frontend problems in high-performance environments
Engineering culture focused on quality, performance, and continuous improvement

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Do you have avalaibility to work in hybrid model 3/2 in our offices located in Logroño, Barcelona, valencia or Alcobendas? If yes, please, tell us which one

Have you worked in an international enviroment speaking in english? What is your current level?

Have you worked on performance-critical frontend rendering (e.g., Canvas, WebGL, or heavy DOM optimization)

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Which of these have you worked with professionally? *

Advances Javascript (ESNext)

Canvas API(WebGL

Web Workers

None of them

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Frontend Engineer (Performance & UI Rendering)

Mission:

Responsibilities:

Requirements:

What We Offer:

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