Kostis Saitas Zarkias is a Senior AI Research Engineer currently at Mozilla Data Collective, operating at the intersection of machine learning research and production engineering. With over a decade of experience bridging academic research and deployed AI systems, his work has ranged from R&D development on LLM alignment and guardrails to developing scalable platforms and multimodal pipelines for speech, text, and agentic applications. Beyond engineering, he combines technical expertise with active community building through Plateia AI, a grassroots initiative mapping AI’s social impact across Greece, collaborates and advises artists on navigating AI tools ethically in their creative practice, and guides AI strategy for an established MedTech company. He holds an M.Sc. in Machine Learning from KTH Royal Institute of Technology, Sweden.