Principal Software Engineer
Flutter InternationalJob title: Principal Software Engineer
Location: Sofia, Bulgaria
Overview of the role:
We are transforming our Sofia studio into a high-performing Technology Hub, focused on building scalable, high-quality game development capabilities.
As part of this transformation, we are looking for a Principal Software Engineer to play a critical role in shaping our technical direction, improving how we build software end-to-end, and enabling our teams to deliver faster, with higher quality.
This is a hands-on technical leadership role. You will be expected not only to set direction, but also to go deep when needed — solving complex problems, guiding teams, and leading by example.
Working closely with the Head of Technology, you will operate across multiple squads as a technical authority, ensuring we make the right decisions, maintain high engineering standards, and successfully deliver the technology changes required to support our growth.
This role follows a hybrid approach to working, allowing you to combine working from home with working in our modern offices. These discussions are between you and your manager to find the best pattern for you both, while recognising that quality time together is essential for keeping us mission-aligned.
Our teams work from a lively location nestled within this historic city. Enjoy the best of both worlds with winter and summer offices, tantalizing free snacks and a gaming paradise for endless entertainment.
What you’ll do:
Key Responsibilities
Act as a technical authority across multiple squads, guiding architecture, design, and engineering decisions
Drive the execution of technology strategy and transformation initiatives within the organisation
Lead and influence major technical changes (platform evolution, tooling, frameworks, performance improvements)
Ensure high engineering standards across scalability, performance, security, and maintainability
Take a hands-on approach to solving complex technical problems and unblocking teams
Partner closely with the Head of Technology and Solution Architects to define and evolve system architecture
Establish, promote, and enforce engineering best practices (coding standards, testing, CI/CD, observability)
Act as a custodian of software design, ensuring consistency and quality across systems
Proactively identify gaps, inefficiencies, and risks, and drive solutions without requiring direction
Support teams in breaking down complex problems into clear, executable work
Enable cross-team alignment and reduce silos across engineering teams
Leadership & Impact
Mentor and coach engineers, tech leads, and senior engineers to elevate technical capability
Create an environment where teams are autonomous but aligned, with clear technical direction
Act as a multiplier, improving the effectiveness of multiple teams rather than a single squad
Support hiring and contribute to technical assessment and capability building
Champion a strong engineering culture focused on ownership, quality, and continuous improvement
Build strong working relationships across engineering, product, delivery, and platform teams
Lead by example through hands-on contribution and technical excellence
What you’ll bring:
Technical Leadership
Proven experience operating as a Principal / Staff-level engineer or equivalent
Strong track record of owning technical direction across multiple teams or domains
Ability to make high-impact technical decisions with long-term implications
Experience leading large-scale system design and architectural evolution
Engineering Excellence
Deep understanding of modern software engineering practices, including:
Test-driven development (TDD)
CI/CD and automation
Observability, monitoring, and performance optimisation
Experience improving software development lifecycle efficiency and reducing delivery friction
Strong advocate for clean architecture and maintainable systems
Hands-On Expertise
Strong hands-on experience with:
Node.js, TypeScript, JavaScript, React
Java (backend systems)
Experience working with:
AWS, Docker, Kubernetes
GitHub workflows / modern CI/CD pipelines
Ability to prototype, validate, and implement solutions directly
AI & Innovation
Practical understanding of AI tools and their application in software development
Ability to identify and implement AI-driven improvements in engineering workflows, tooling, or products
Collaboration & Communication
Strong communication and stakeholder management skills
Comfortable working across multiple teams and disciplines
Ability to clearly explain complex technical concepts to non-technical stakeholders
Ways of Working
Experience in Agile environments (Scrum, Kanban)
Strong prioritisation and decision-making skills
Self-driven, proactive, and comfortable operating with minimal supervision
Nice to have:
Experience in the gaming / gambling industry
Experience working on high-scale, real-time systems
Public GitHub repository or portfolio of work
What Success Looks Like
Teams make better, faster technical decisions with clear direction
Systems become more scalable, maintainable, and consistent
Engineering standards are well understood and consistently applied
Technical debt is actively managed and reduced
Teams are more autonomous, confident, and effective
Technology changes are successfully delivered with minimal disruption
It’s ok if you don’t think you tick every box on this list. We love people who want to challenge themselves and are passionate about what they do. If you believe you can contribute in some areas and are eager to learn, we encourage you to apply.
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 bonus
30 days paid leave
Health and Dental Insurance for you, your partner and your children (if you all live at the same address)
Personal life insurance and disability coverage
Wellbeing fund
Continuous learning support for certifications and career growth
550 EUR gift for newborn family member
26 weeks Maternity leave at 100% pay and 4 week secondary (Paternity) also at 100% pay, no eligibility period applies
A sports’ card membership valid across the country
Discounts as a compliment form us among different services
Monthly food vouchers
Equal opportunities:
At Flutter 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 work we are doing on Inclusion and Belonging here: https://careers.flutterinternational.com/working-at-flutter-international/diversity-equity-inclusion/
The group:
Flutter Studios is a proud member of the Flutter Entertainment family, a global leader in sports betting, iGaming, and entertainment. We're not just another company; we're listed on both the prestigious FTSE 100 index on the London Stock Exchange and the New York Stock Exchange (NYSE). What sets us apart is our world class brands, cutting-edge products, and our International division includes our operations in over 100 global markets and offers sports betting, casino, poker, rummy and lottery, mainly online. What truly defines us is our commitment to ensuring that the excitement 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.