Enabling creativity since 2006

Miha Mikek is the Founder and CEO of Celtra. Born in Slovenia, he started several companies before founding Celtra in 2006 while completing his graduate studies at Babson College. Under his leadership, Celtra pioneered a self-service platform that made rich media ads on mobile truly scalable. His work fueled exponential growth from 2011 to 2016, establishing Celtra as a global leader in enabling media companies, advertising platforms, service providers, and advertisers. Miha led the company through multiple rounds of venture capital financing, culminating in a successful majority stake acquisition by STG, where he partnered with the new investors. He continues to drive Celtra’s innovation and investment in market-first solutions like Creative Automation—helping the world’s largest advertisers scale creative and streamline creative and media workflows to help companies achieve better advertising outcomes.

Outside the office
Beyond Celtra, Miha is an advisor to tech founders, an active board member, and an investor in technology companies. After 16 years in Boston, he now lives in Geneva, Switzerland, with his wife, Maja (Celtra’s co-founder and CFO), and their children, Sofia and Lev. He finds inspiration in outdoor sports, family adventures, and the pursuit of bold new ideas.

At Celtra from Day 1, our Co-Founder and CFO Maja has laid a solid foundation for the Finance and HR functions at Celtra, grounded always with common sense and the ambition to make Celtra a great place to work and grow. Passionate about Celtra’s values and culture, Maja’s day-to-day motivation is employee activation, their engagement, holistic growth and bringing out that “spark in the eyes” of her coworkers. With creativity, a can-do attitude, and a supportive, healthy environment, Maja believes in the potential of each person to make a big impact at Celtra and to contribute to the Company’s success.

Outside the office
In her free time, Maja prioritizes spending time with her two kids and enjoys family activities including skiing, biking, hiking, surfing, reading, traveling, and in-depth discussions of books, ethics, and life. She is a peace-lover and a big gratitude-giver.

With over 20 years of experience across various industries, Uroš has built an impressive range of skills—from starting in automotive at Goodyear as an analyst to strategic consulting at McKinsey, then later holding leadership roles at Valicon, Mercator, and Zavarovalnica Triglav. As COO at Celtra, he brings together his invaluable range of expertise in CRM, business analytics, and strategy into the AdTech space.

Outside the office
When he’s not turning data into meaningful insights that drive customer-focused strategies, he’s a family man with two kids, an avid reader, a lover of the sea, and a dedicated foodie.

Matic has always had a passion for technology, a fascination that began in childhood when he would eagerly disassemble computers—sometimes without managing to reassemble them. This curiosity shaped his perspective, turning failures into valuable learning experiences. After pursuing a degree in computer science, he joined Celtra, where he has grown from a hands-on technical role to leading teams and departments. Matic enjoys the constant challenges and the opportunity to collaborate with talented people, which keeps every day exciting.

Outside the office
Outside of work, he’s just as hands-on with cars, spending his free time racing, fixing, and learning about them.

Ryan Cook is the Global SVP of Sales at Celtra, where he combines his passion for innovative technology with a deep commitment to building solutions that work. With a career rooted in ad tech, he’s been instrumental in scaling businesses like HeyWire (acquired by Salesforce) and Nexage (acquired by AOL). He helped launch Teads’ programmatic business from humble beginnings to a 9-figure value, leading to its sale to Altice and later its merger with Outbrain. He’s also held leadership roles at Digital Turbine and Criteo, focusing on performance advertising and commerce media.

Outside the office
Outside of work, Ryan enjoys experimenting in the kitchen with hopes of one day opening a restaurant. As the oldest of four siblings and an uncle to three, he values family, creativity, and setting the bar high—both in life and work.

Miha has been passionate about technology from the beginning. As a kid, he built gaming PCs from scratch, a hobby that sparked a lifelong interest and eventually led him to earn a PhD in electrical engineering. He later transitioned into software engineering, spending several years coding at a tech startup before joining Celtra. Since then, his role has evolved from hands-on development to mentoring others, leading teams, and overseeing engineering departments. He’s driven by a deep curiosity for emerging technologies and a dedication to building innovative, high-quality products.

Outside the office
Outside of work, Miha loves spending time with his family, traveling around the world, and tinkering with smart home tech to make everyday life a little more connected and efficient.

Celtra’s head lawyer since 2015, Megan handles everything from contracts and data protection to corporate governance, always aiming to protect the company while helping it grow. As a litigator and former athlete, she brings a strong team spirit and a drive to excel in everything she does.

Outside the office
When not at work, she loves to spend time with her three kids, often at the ice hockey rink or taking on new challenges together.

A Sr. Marketing Director at Celtra, Tanja is passionate about making advertising better, one ad at a time. With over a decade of experience in the digital advertising space, she’s honed extensive design and marketing knowledge by heading multiple creative and production teams. Her blend of hands-on design and marketing experience, paired with sharp leadership skills, helps her tackle creative and technical challenges with ease when collaborating with major global brands.

Outside the office
A proud mom of three, Tanja channels her boundless creativity into her free time, when she loves exploring arts and crafts with her family.