AI-Integrated Front-End Developer – Valencia

We offer you the opportunity to join the leading Spanish company in the IT sector, with more than 25 years of experience and one of the most solid track records as a provider of technological solutions for companies.

We are a growing company with more than 400 employees and offices in Logroño, Madrid, Barcelona, Seville and Valencia.

Since August 2013, we have been part of the IONOS Group, Europe’s leading digitalisation partner for small and medium-sized companies.

In short, we are a multicultural team that’s passionate about technology, bringing our professional experience from over a dozen countries: Germany, Argentina, Spain, the United States, France, the Philippines, Italy, Poland, Portugal, the United Kingdom, Romania…

The Mission

You will own the JavaScript layer in EuroOffice, setting the bar for code architecture, loading and rendering performance, and deep bug investigation. In this role, AI is not a separate specialty, but a core working method woven into how you build, debug, and refine software.

Key Responsibilities

• Coding Excellence:Write and review clean, well-architected JavaScript/TypeScript with sound state management, creating code that both engineers and AI models can easily reason about.

• Rendering & Loading Performance:Identify and fix performance bottlenecks (TTI, load time, unnecessary re-renders, bundle bloat) across DOM and Canvas surfaces.

• Feature Refinement:Continuously sharpen shipped features based on production usage patterns and real-world edge cases.

• Bug Research:Trace and resolve complex, non-obvious issues across large and partially undocumented codebases.

• AI Integration:Utilize AI across all workflows to accelerate implementation, analyze logs/traces, and maintain real-time documentation.

Core Requirements

• Expertise in Modern JS/TS:High standards for code quality, architectural integrity, and browser performance (rendering pipeline, profiling via DevTools/Lighthouse).

• AI-First Orchestration:Demonstrated experience using AI as an everyday development multiplier. You let AI handle the initial pass while you bring the technical judgment, validation, and architectural rigor.

• English Fluency:English domain for daily technical communication and team collaboration.

• Debugging & Legacy Navigation:Comfort working with complex, legacy code and pursuing non-linear bug investigations to resolution.

• Bonus:Familiarity with Canvas or WebGL.

At Arsys we value diversity and welcome all applications regardless of, for example, gender, nationality, ethnic or social origin, religion, disability, age, as well as sexual orientation and identity, physical characteristics, marital status or any other irrelevant factor subject to applicable law.