Engineering \& Development \| Senior Senior Czech Republic Montenegro Serbia Slovakia Spain Europe \| Czech Republic Montenegro Serbia Slovakia Spain Europe August 13, 2025 ### **About the company** First Line Software works with some of the world's top businesses and organizations in industries like healthcare, *data engineering*, warehouse automation, retail digitalization, mobile app development, and e\-commerce. Our projects are as varied as our people, and our people are as talented as they come. We prefer working as a transparent and supportive team, who shares our knowledge as well as our success. Let's see what we can create together! ### **The project and your role** Building high\-performance, user\-centric digital experience websites aimed at delivering personalized content and seamless user journeys. The project leverages Optimizely for content management alongside a React\-based frontend. **Responsibilities:** * Develop and maintain frontend features of the web platform using React and Optimizely * Collaborate with backend developers, designers, and content managers to deliver high\-quality digital experiences * Optimize application performance and ensure responsive, cross\-browser compatibility * Write unit and integration tests to ensure code quality * Participate in code reviews and mentor junior developers * Continuously improve development processes and stay updated with industry trends * Ensure alignment with design and UX requirements for a seamless user experience ‍ ### **Your skills** * 4\+ years of experience in frontend development * Proven track record of building scalable and maintainable React applications * Experience working with Optimizely CMS for content\-driven websites * Strong understanding of performance optimization techniques for web applications * Ability to write clean, modular, and well\-documented code * Strong problem\-solving skills and attention to detail * Good communication skills and ability to work collaboratively in a cross\-functional team * English: Upper\-intermediate or higher (for daily communication with international teams) **Must have:** * React.js (advanced proficiency) * JavaScript (ES6\+) * Experience with Optimizely CMS / Optimizely Content Cloud * HTML5, CSS3, SASS/LESS * RESTful APIs integration * Version control systems (Git) * Responsive and cross\-browser development practices **Nice to have:** * TypeScript * Optimizely Feature Experimentation (Full Stack) * Headless CMS integrations * Experience with CI/CD pipelines * Unit and integration testing (Jest, React Testing Library) * Familiarity with accessibility standards (WCAG) * Experience with cloud platforms (Azure, AWS) ‍ ### **What we can offer** **The FLS difference** * Our modern stack projects are the right mix of exciting and challenging * Gain access to our diverse range of training programs, courses, and certifications * Choose your work style \- remote, on\-site or hybrid in one of our stunning offices. We offer the freedom of flexible working hours * Enhance your language skills with our corporate English classes * Work from anywhere and explore the world with our Workation program ### **Language Proficiency** No items found. Our Hiring Process**Getting started with us** --------------------------- Here's what you can expect when you send us your application### **Step 0** ### **Tech Talent Hunt** Be scouted or apply for your role### **Step 1** ### **Meeting \& Connecting** Our first step to building lasting relationships ### **Step 2** ### **Uncovering Potential** Your HR interview ### **Step 3** ### **The Code Challenge or Technical Interview** It's time to show what you can do best! ### **Step 4** ### **Client’s Interview** Demonstrating expertise to our future partners ### **Final** ### **The Last Piece of the Puzzle** Job offer to finalize our tech team **Join our team of innovative thinkers** ======================================== **Let’s talk!** --------------- Have any questions? Fill out the form and our team will be in touch!