Staff Software Engineer - Experimentation & Decisioning Platform

Checkout.com; Greater London; Hybrid; GBP 110,000 - 160,000; Full time

Job summary

Checkout.com is seeking a Staff Software Engineer to lead and scale our Experimentation and Optimisation platform within the Payments Performance pillar. You’ll guide architectural priorities across multiple teams, balancing technical excellence with impact, and build automated experimentation at a global scale.

You will mentor engineers, partner with Data Science and ML teams, and own the technical direction of complex, cloud-based systems using AWS and Go.

Qualifications

• Experience leading technical direction for complex backend platforms.
• Strong background in building and operating cloud-based distributed systems (AWS).
• Excellent Go (Golang) programming skills with low-latency architecture focus.
• Proven track record implementing experimentation or feature-flag infrastructures.

Responsibilities

• Drive long-term technical direction for the Experimentation and Optimisation platform.
• Collaborate with Data Science, Platform and ML teams to shape what we build.
• Mentor engineering teams and raise engineering standards across the pillar.
• Translate requirements into clear engineering roadmaps and architecture decisions.

Skills

Technical leadership

Distributed systems

Go (Golang)

Experimentation systems

Mentorship

Communication

Data-driven

Initiative

Adaptive experimentation ML

Job description

Company Description

We’re Checkout.com. You might not know our name, but companies like eBay, Spotify, Klarna, Uber, and Sony do, because we’re behind many of the digital experiences you use every day. We are where the world checks out, enabling over 10 billion transactions yearly for more than one billion global shoppers. Whether you want to book a holiday, order food, renew a subscription, or check out online, there’s a good chance our tech powers the payments behind the scenes. Our platform helps the most ambitious businesses deliver effortless digital experiences, at scale. If you want to do career-defining work, you’ve come to the right place. We move fast, think globally, and believe great teams are built by hiring exceptional people with conviction, curiosity, and the desire to make an impact. With 20 offices across six continents and London as our HQ, we’re shaping the future of fintech – and we’re just getting started.

The role

Global payments are complex, high-throughput, and ever-evolving. At Checkout.com, our software engineers develop the next-generation financial technologies that empower merchants to optimize acceptance rates, combat fraud and unlock seamless customer experiences. As a Staff Software Engineer within our Payments Performance pillar, you will step into a critical role of strategic technical leadership. It is rooted in your profound depth of technical expertise and a wide breadth of organizational influence. You will guide the technical approach for your group, aligning multiple engineering teams on architectural priorities, unblocking complex obstacles, and balancing technical excellence with pragmatism for impact. We are looking for someone with a background building robust, automated experimentation or decision engines at a global scale.

How you’ll make an impact

• Drive the long-term technical direction and strategy for the Experimentation and Optimisation platform, looking beyond immediate requirements to ensure our solutions are built for impact and scale.
• Collaborate cross-functionally with Data Science, Platform and ML Engineering teams to shape what we build, not just how.
• Act as a coach and mentor to our engineering teams, providing the technical leadership needed to solve complex distributed systems challenges in Go.
• Proactively identify opportunities and take initiative to elevate the engineering standards within the pillar, fostering a culture of continuous improvement.
• Participate, translate, run and execute the collection of requirements and architecture/design initiatives into clear, actionable engineering roadmaps.
• Serve as a role model for engineering excellence, championing best practices in code, architecture and operational excellence.

What we’re looking for

• Technical leadership: setting direction, breaking down complex problems, influencing across teams.
• Extensive, hands-on experience in building, operating and scaling complex, cloud-based distributed systems (we use mainly AWS).
• Excellent programming skills in Go (Golang), with a deep understanding of concurrent, memory-efficient, and low-latency backend architectures.
• A strong engineering background with a proven track record of implementing, owning, and scaling experimentation systems, feature-flagging infrastructures, or similar data-intensive backend systems.
• A proven ability to raise the bar for engineering standards through effective coaching, mentorship, and a relentless drive for platform improvement.
• Strong presentation, communication, and collaboration skills, with the ability to articulate complex technical or statistical concepts to multidisciplinary teams and influence positive outcomes across the organization.
• A detail-oriented and data-driven approach to building infrastructure solutions where accuracy, thoroughness, and low latency are absolutely critical.
• You take initiative and are deeply accountable to your internal customers and engineering colleagues.
• Bonus: experience with implementing solutions for adaptive experimentation ML (contextual bandits, Bayesian optimization or RL-based allocation)

Additional Information

Bring all of you to work

We create the conditions for high performers to thrive, through real ownership, fewer blockers, and work that makes a difference from day one.

Here, you’ll move fast, take on meaningful challenges, and be recognized for the impact you deliver. It’s a place where ambition gets met with opportunity, and where your growth is in your hands.

We work as one team, and we back each other to succeed. So whatever your background or identity, if you’re ready to grow and make a difference, you’ll be right at home here.

It’s important we set you up for success and make our process as accessible as possible. So let us know in your application, or tell your recruiter directly, if you need anything to make your experience or working environment more comfortable.

Life at Checkout.com

We understand that work is just one part of your life. Our hybrid working model offers flexibility, with three days per week in the office to support collaboration and connection.

For a closer look at daily life at Checkout.com, follow us on LinkedIn and Instagram.