Thibault Sottiaux

Thibault Sottiaux is a Belgian software engineer and product leader who serves as a Member of Technical Staff at OpenAI, where he leads work on Codex and contributes to ChatGPT and other core products.^[1] In public interviews and profiles, he is described as the head of ChatGPT and Codex or as OpenAI's head of product for its core products, reflecting responsibility for major offerings such as the API, agent infrastructure, enterprise products, ChatGPT (including ChatGPT Work), and Codex.^[7]^[8]^[6]

Education

He earned a Bachelor of Applied Science in Computer Science and Applied Mathematics and a Master of Science in Computational and Applied Mathematics from UCLouvain in Belgium.^[1]

Early Career

Thibault Sottiaux began his career in Belgium, working in research and development at N-SIDE, where he contributed to applied optimization and analytics projects. Alongside this early work, he held short-term roles as a junior consultant at ProCapital, a visiting software engineer at LSM Conseil, and a teaching assistant at UCLouvain.^[1]

Google

Thibault Sottiaux joined Google in London in January 2015 as a Software Engineer and was later promoted to Senior Software Engineer, holding engineering roles there until April 2018. After leaving Google, he moved to Google DeepMind as a Staff Software Engineer, where he later led a 20+ software engineering team responsible for AI and machine learning workflow infrastructure for DeepMind research, and subsequently a 50+ multidisciplinary team as Gemini Human Data Lead, focused on fine-tuning data and human evaluations for the Gemini model family.^[1]

Career

OpenAI — Codex Engineering Lead

In 2025, Thibault Sottiaux joined OpenAI as the engineering lead for Codex, described as OpenAI's agentic coding system.^[2] Codex is presented as a software engineering agent that operates in sandboxed environments, collaborating across multiple layers of the software development stack rather than focusing on a single tool or feature.^[2] Sottiaux has described the team's "agent-first" approach, in which they prioritize building a broadly capable agent and only then decide which specific product endpoints to surface, positioning Codex as a general-purpose coding agent rather than a narrowly scoped assistant.^[4]

Under his guidance, the concept of a "harness" was emphasized — a lightweight software scaffolding that orchestrates tools, context, and safeguards around the agent but is intended to become simpler as model capabilities improve.^[2]^[4] In an OpenAI Forum event, he was introduced as a Member of Technical Staff at OpenAI who leads Codex, described there as OpenAI's software engineering agent evolving beyond code toward broader knowledge work and productivity use cases.^[9]

Sottiaux discussed Codex's design and development publicly alongside OpenAI co-founder Greg Brockman on the OpenAI Podcast, in a conversation about the future of coding with AI and Codex's potential beyond traditional programming tasks.^[3] He appeared on Software Engineering Daily with Codex product designer Ed Bayes to explain Codex's architecture, the co-evolution of models and harnesses, and its place in the broader shift toward AI coding agents.^[2] He also initiated the "100 Days of Codex" program on the social media platform X, highlighting and rewarding individuals who demonstrated creative or impactful uses of Codex.^[5]

OpenAI — General Manager, ChatGPT and Codex

By 2026, Thibault Sottiaux was leading work on ChatGPT and Codex and was described by external outlets as a central product leader for OpenAI's core products. A Wired profile presented him as the OpenAI engineer leading ChatGPT's transformation into a personalized AI agent "super app," highlighting his role in turning frontier models into an everyday assistant.^[6] In a TechCrunch interview, he was introduced as the head of product for OpenAI's core products, including the API, agent infrastructure, enterprise offerings, ChatGPT (including ChatGPT Work), and Codex, in a discussion focused on bringing AI agents to broader knowledge work.^[8]

As the head of ChatGPT and Codex, he appeared on the Silicon Valley Girl podcast, where he discussed AI agents for everyone and how future products could benefit even people who do not actively use AI tools.^[7] Across these public appearances, he has been portrayed as overseeing OpenAI's core user-facing and platform products, including ChatGPT and Codex, and shaping how AI agents are integrated into everyday professional and personal workflows.^[5]^[9]^[6]