Marios Assiotis

Hands-on technology executive · Most recently CTO Tubi & CTPO AdRise

Work Experience

Parental Leave / Sabbatical

Apr 2025 – Present

Taking planned time off following the birth of my first child.

  • Angel Investing and advising early-stage startups
  • AI R&D on building secure by design agentic workflows

AdRise

CTO & CPO

Mar 2024 – Apr 2025

Tubi

CTO

Jan 2016 – Mar 2024

Scaled Tubi from early-stage startup to a $1B revenue streaming platform.

  • Grew revenue from a million to a billion.
  • Built and led global engineering organization (10 → 250 engineers across US and China).
  • Led company through $500M FOX acquisition and post-acquisition integration.
  • Introduced Machine Learning and Experimentation as core company tenets early on and embedded them across product, advertising, and growth teams.
  • Built custom machine learning, experimentation, advertising, and video ingestion platforms supporting Tubi's rapid scale, including systems for content discovery, search, ad targeting, and content understanding.

Founding member of FOX's centralized AdTech business unit, AdRise, responsible for integrating Tubi's acquired advertising platform across FOX properties.

  • Consolidated teams, fragmented platform capabilities and vendor contracts, reducing duplication and improving cost efficiency by 200%.
  • Led rapid delivery of a Unified Identity Graph to power all current and future AdTech initiatives, compressing what was a 24-month roadmap into 6 months via scope rationalization and execution rigor.

Sidelines Inc

Co-Founder & CTO

Nov 2011 – Jan 2016

Co-founded a native advertising platform combining rich media, user-generated content, and algorithmic distribution.

  • Designed Machine Learning based distribution algorithms for matching branded content with relevant editorial contexts.
  • Built a gamification system that encouraged user generated contributions that were then used for advertising on clients' sites.

Microsoft

Senior SDE

Aug 2006 – Nov 2011

Worked on the Hotmail (now Outlook.com) storage platform during a major scale expansion.

  • Scaled existing legacy storage architecture, enabling mailbox capacity expansion from 25MB to 2GB.
  • Applied control theory and erasure coding techniques to improve data durability and mitigate bit-rot in large-scale storage systems.
  • Applied operations research techniques to improve storage capacity planning and infrastructure efficiency.

Education

Massachusetts Institute of Technology

Cambridge, MA

2002 – 2006

BSc in Computer Science and Engineering

Publications & Awards

  • "A Distributed Architecture for MMORPG" — ACM SIGCOMM (2006)
  • Bronze Medal — Balkan Olympiad in Informatics
  • Represented Cyprus in two International Olympiads in Informatics (IOI)
  • Microsoft True North Innovation Award

Internships

Microsoft

Software Engineering Intern

Jun 2005 – Sep 2005

Internal payments platform in C#.

Apple

Software Engineering Intern

Jun 2004 – Sep 2004

Bridged Objective-C and the WebObjects framework.

EDAMS Technology

Software Engineering Intern

Mar 2002 – Aug 2002

Built software for water utility companies around the world using Delphi.

Languages

  • Greek Native
  • English Native
  • Chinese Elementary