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Senior Backend Engineer - Trading Platform

Engineering – London, London, City of
Department Engineering
Employment Type Full-Time
Minimum Experience Experienced

Blis is an award-winning, global leader and technology innovator in location-based data, analytics, and advertising. We help brands such as McDonalds, Samsung, and Unilever to understand and reach their current and potential customers and drive real-world business outcomes. With 24 offices across 5 continents, and over 200 people on the team, we are a truly international company with both a global culture and scale. We’re headquartered in London, venture capital backed, financially successful and stable, and looking forward to continued growth. We’d love it if you could join us on the journey!

We are looking for brilliant, creative, curious, and experienced Backend Engineers to support our Trading team and infrastructure. This team delivers internal and customer-facing SaaS applications for managing complex media and data campaigns, providing rich reporting and visualisations, and packaging deep analytics backed by our big data and machine learning technologies. They are also responsible for the backend business logic and applications behind our real-time bidding platform, which processes over 400,000 requests a second with millisecond-level latencies. We use technologies such as Angular, Javascript, Java, Scala, and C++ and we’re constantly looking at how we can do things better. This is a growing team of 17 people across two product sub-teams with big responsibilities and exciting challenges ahead of it, as we look to reach the next 10x level of growth. Our employees are passionate about teamwork and technology and we are looking for someone who wants to make a difference within a growing, successful company.

At Blis, Backend Engineers are a combination of software and devops engineers. They actively write code, typically in Java, but also help own our applications and application ecosystems. They help us innovate, build, and support our algorithmic, management, reporting, and other decisioning systems and integrate with our big data technologies. They work in cross-functional teams with data and frontend engineers, but also data scientists and other people across the business. Across the team, everyone supports each other through mentoring, brainstorming, and pairing up. They have a passion for delivering products that delight and astound our customers and that have a long-lasting impact on the business. They do this while also optimising themselves and the team for long-lasting agility, which is often synonymous with practicing Good Engineering. They are almost always adherents of Lean Development and work well in environments with significant amounts of freedom and ambitious goals.

This is a full-time, permanent position based in London.

The Role:

  • Innovate, implement, support, and iterate on our application infrastructure and online and offline codebases.
  • Support,  mentor, and pair with other members of the team to advance our team’s capabilities and capacity.
  • Help Blis identify and take advantage of new and innovative opportunities for commercial and technical growth.


  • 5+ years experience as a backend developer and architect for complex, customer-centric web and offline applications.
  • Excellent knowledge of Java (bonus for Scala, Python, and/or Javascript).
  • Advanced knowledge of the Spring Framework.
  • Mastery of RESTful API and web serving concepts.
  • Familiarity with distributed systems and concurrency topics.
  • Experience designing and implementing secure, highly scalable systems.
  • Expertise with relational and non-relational database concepts.
  • Excellent knowledge of data structures and algorithms at-scale.
  • Mastery of debugging and optimising data-centric Java applications.
  • Comfort with server-side Linux and cloud infrastructures (AWS or GCP).
  • Knowledge of Good Engineering and when to go fast and when to go slow.
  • Degree in Computer Science, Software Engineering, or similar.


  • Experience with CI/CD, source control systems, and container technologies, such as Jenkins, Docker, Kubernetes, and Git.
  • Knowledge of commercial blockchain technologies, such as IBM’s HyperLedger.
  • Knowledge of machine learning algorithms and how to implement them in production environments.

What Blis Can Offer:

Opportunity to work with a market leader in the data technology space, with significant visibility across the business, and working with groundbreaking technology.

  • Great office in central London, based in Holborn.
  • Beer Friday - to help see in the weekend.
  • Free breakfast.
  • Blis bank-holiday - an extra bank-holiday courtesy of Blis.
  • Free eye tests.
  • Casual dress - no suits required, unless of course you like them!
  • Fresh fruits.
  • Childcare vouchers.
  • Cycle scheme.
  • Day off on your birthday!
  • Competitive packages.
  • Early finish Friday - because you deserve it.
  • Gym – subsidised gym membership at Fitness First.
  • Pensions - saving for the future?

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.

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