AI-Integrated Front-End Developer

arsys; Alcobendas; Hybrid; EUR 55,000 - 75,000; Full time

Benefits offered by this job

Health insurance

Daycare allowance

Meal vouchers

Flexible working hours

Hybrid work

Job summary

Arsys, a leading Spanish IT company with offices in Logroño, Madrid, Barcelona, Seville and Valencia, seeks a frontend expert to own the JavaScript layer of EuroOffice. You will drive code architecture, optimize rendering performance, and integrate AI into daily development and debugging workflows.

You will work across modern JS/TS, embrace AI as a development multiplier, and collaborate in English with a multicultural team.

Qualifications

• Expertise in Modern JS/TS with performance focus.
• AI-first orchestration in daily development.
• English for technical collaboration.
• Experience debugging legacy code and complex systems.

Responsibilities

• Coding Excellence: write and review clean JS/TS.
• Rendering & Loading Performance: fix bottlenecks (TTI, load time, re-renders).
• Feature Refinement: sharpen shipped features based on usage patterns.
• Bug Research: trace and resolve complex issues across large codebases.
• AI Integration: utilize AI across workflows to accelerate implementation.

Skills

Modern JS/TS

AI-First Development

Browser performance

English fluency

Debugging legacy code

Tools

DevTools/Lighthouse

Canvas/WebGL

Job description

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.

Benefits

• Fixed salary and flexible benefits such as health insurance, daycare allowance, and meal vouchers.
• Flexible working hours to organize your schedule according to your needs.
• Ability to work hybrid in any of our offices located in Logroño, Madrid, Barcelona, Seville or Valencia.
• Invitation to our Arsys events, held twice a year, where we team build and throw a great party for our employees.
• Personalized training in cutting-edge technologies, certifications, or any area that interests you.
• Various employee discounts for activities and products.

We have a motivated, innovative team that is continuously learning. A culture where your opinion and initiative matter. We want to hear your ideas and see you put them into practice.

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.