Flutter

Senior Front End Developer

Job title: Senior Frontend Developer

Location: Sofia, Bulgaria

Overview of the role:

We are the team behind the front end of the Sportsbook platform, the part users actually see and interact with when they place bets, check scores, or browse events. Our job is to turn complex data and logic into a fast, user-friendly experience that works smoothly across different brands and devices.

We build and maintain a multi-brand platform, which means we support several unique Sportsbook experiences using a shared codebase. This requires a strong focus on modular design, reusable components, and smart architecture. We rely on modern tools and frameworks like Angular, TypeScript, RXJS, and Nx Monorepo setup, and we follow a component-driven approach to ensure consistency across the board.

We are currently looking for a Senior Frontend Developer to join our team in Sofia, Bulgaria.

As Senior Frontend Developer is an experienced software engineer with deep expertise in frontend technologies, architecture, and development best practices. This role is responsible for aligning web design with user experience requirements, optimizing applications for maximum performance and scalability, and ensuring brand consistency across all web interfaces.

In this position, you will develop and maintain a large-scale Angular application, collaborating closely with designers, product managers, backend engineers, and QA to ensure seamless integration and high-quality user experiences.

Beyond hands-on coding, a Senior Frontend Developer plays a critical role in mentoring junior engineers, driving technical excellence within the squad, and ensuring adherence to best practices. You will actively contribute to the squad's technical execution while also influencing broader architectural and technical decisions. Your work will help ensure that the web applications we deliver are scalable, maintainable, and aligned with our squad’s product vision.

What you’ll do:

• Translate web design mockups and feature requirements into functional, mobile-friendly websites.
• Ensure cross-browser compatibility and optimize applications for maximum speed and scalability.
• Write clean, maintainable, and reusable code following best practices and design patterns.
• Conduct and participate in code reviews to ensure high quality and consistent code standards.
• Write and maintain unit, integration and E2E tests and help maintain existing test coverage to ensure software quality.
• Collaborate closely with other teams to implement a seamless user experience.
• Debug and troubleshoot frontend issues, perform root cause analysis and implement reliable solutions.
• Participate in Agile ceremonies (daily standups, sprint planning, retrospective)
• Mentor and support junior developers through knowledge sharing, code review and code pairing sessions.
• Stay up to date with emerging front-end technologies and propose improvements.
• Related duties as assigned.
• 6+ years of professional experience building modern web applications.
• 3+ years hands on experience with:
  • HTML, CSS, JavaScript, and modern frontend frameworks (Angular 16+, React, Vue, RxJS, reactive state management, etc.).
  • Frontend Architecture including:
    • Micro frontends (Webpack Module Federation, Single SPA)
    • Monorepos (e.g., Nx, Turborepo)
• Strong proficiency in:
  • Typescript, modern JavaScript (ES6+), HTML5 and CSS3
  • CSS Preprocessors (SCSS/SASS/LESS), Tailwind CSS
  • Working with RESTful services, APIs and WebSockets
  • Package managers (npm/yarn)
• Solid understanding of design patterns and component driven development.
• Strong understanding of web performance optimization, including:
  • JavaScript optimization (e.g. lazy loading, bundle analysis and caching)
  • CSS optimization (e.g., critical CSS, CSS coverage)
  • Image Optimization (compression, format(webp))
• Hands on experience with browser testing and debugging tools.
• CI/CD experience:
  • Setting up and maintaining build pipelines (Building and Code quality, linters, unit test as part of release, integrations)
  • Deploying frontend applications
• Experience with frontend tooling:
  • Build tools (e.g., Webpack, Vite)
  • Code Quality like Prettier, ESLint, TypeScript
• Hands-on experience with version control systems such as Git
• Effectively collaborate with product managers, backend developers, designers, QA and other team members.
• Stay up to date with emerging technologies
• Relevant soft skills like communication and problem-solving mindset

What you’ll bring:

• Professional experience building dynamic frontend web applications and websites
• Hands on experience with HTML, CSS, JavaScript, and modern frontend frameworks (Angular 16+, React, Vue, RxJS, reactive state management, etc.).
• Good knowldedge of RESTful services, APIs and WebSockets
• Experience with browser testing and debugging tools, like Chrome DevTools
• Hands-on experience with version control systems such as Git
• Ability to effectively collaborate with product managers, backend developers, designers, QA, and other team members.
• Staying up to date with emerging technologies
• Relevant soft skills like communication and problem-solving mindset

Why choose us:

Aside from a generous base salary, we have a fantastic benefits & rewards program that is designed to encourage personal and career development.

• Discretionary annual performance bonus
• 30 days annual leave
• Health and Dental Insurance for you, your partner and your children (if you are all registered at the same address)
• Personal life insurance and disability coverage
• A personal interest allowance to let you learn something new or pursue a hobby
• External learning support of up to £2,000 or equivalent in local currency, dedicated 4 learning “Power Hours” every month during office time, full access to the Udemy and Mindtools platforms, in-house leadership program and many other training opportunities for developing your skills and progressing your career
• Looking to extend your family? You will receive a cash gift of 1,000 BGN for your new addition whilst working for us
• A sports’ card membership valid across the country
• Food vouchers

Equal opportunities:

At Flutter International we are committed to creating an inclusive environment where our people can be their authentic selves and thrive. We embrace and celebrate diversity, respecting all our uniqueness and differences.

We welcome you to let us know whether you have any accessibility needs. All you need to do is email us at talent@flutterint.com. Your journey with us is focused on ensuring you have what you need to be your best self.

Learn more about the works we are doing on Inclusion and Belonging here: https://careers.flutterinternational.com/working-at-flutter-international/diversity-equity-inclusion/

The group:

Singular is a proud member of the Flutter Entertainment family, a worldwide leader in sports betting, gaming, and entertainment. We're not just another company; we're part of the FTSE 100 index on the London Stock Exchange and listed on the New York Stock Exchange (NYSE). What sets us apart is our exceptional blend of brands, top-notch products, and a global presence that spans across 40 countries. What truly defines us is our commitment to ensuring that the thrill of gaming and entertainment is experienced in a responsible and sustainable way. Our remarkable team of over 8,000 colleagues drives this vision, spread across 28 offices worldwide