Senior Scala Engineer at LoopMe · Krakow

LoopMe is an AI company solving one of advertising's hardest problems: making brand advertising actually measurable — and making it perform. Our platform runs patented machine learning models across billions of consumer signals in real time, optimising campaigns toward outcomes like purchase intent, brand lift, and foot traffic rather than proxy metrics like clicks. The result is 2–5x better performance than industry benchmarks, at scale.

We operate a high-load programmatic infrastructure — processing millions of ad requests per second with sub-200ms response times globally. This isn't a layer on top of someone else's stack; it's built from the ground up, in-house, by the team you'd be joining. Founded in 2012 and headquartered in London, we now have 400+ people across 19 cities and have sustained 40% revenue CAGR since 2018. The engineering problems here are real, the ownership is genuine, and the scale is significant.

The opportunity You'll own features across our SSP, Adserver, and Exchange products — systems that process hundreds of thousands of requests per second and run real-time auctions to match advertisers with mobile audiences globally. You'll join the adserver team, working in functional Scala while helping drive our multi-year transition to Java.

What you'll do

• Own design, implementation, and testing across our SSP, Adserver, and Exchange products
• Drive the migration of core platform components from Scala to Java
• Partner with engineers, architects, and Operations to ship enhancements and resolve issues
• Lead technical discussions and propose improvements to product and process
• Troubleshoot issues across the application, underlying technologies, and infrastructure
• Develop your technical depth continuously across the stack
• Ship quality work on schedule while driving developer productivity org-wide
• Use AI development tools to streamline the product development process

What you'll bring Essential:

• BS in Computer Science or related field
• 1+ years of Scala programming experience
• 2+ years of Java programming experience
• 6+ years of software engineering experience
• You bring experience designing and implementing microservices in high-capacity, high-traffic, high-availability systems, developed through Agile practice

Nice to have:

• Advertising technology experience
• Experience with Python
• NoSQL databases (MongoDB, Bigtable, Aerospike, etc.)
• Distributed messaging services, like Kafka or PubSub
• Data engineering skills, cloud infrastructure management (AWS or GCP), and familiarity with Git/Bitbucket

What we offer

• Hybrid working — flexible schedule
• 1 month work-from-anywhere
• Annual performance bonus
• Multikafeteria (sport/culture card)