OpenAI Codex Mobile App: AI Coding on iOS & Android

OpenAI's AI coding assistant, Codex, is now available through the ChatGPT mobile app on iOS and Android. This means developers can monitor and steer their AI coding agents from anywhere, without needing a laptop. The feature is rolling out as a preview to all ChatGPT plans, including Free and Go tiers, across all supported regions. This makes it one of the most widely available AI coding agent experiences. It's important to know this is a remote control, not a mobile coding environment. You can start tasks, review outputs, and approve commands, but you cannot write or edit code directly on your phone. Your code and project context remain securely on your machine. Codex handles end-to-end software development tasks, like writing features, fixing bugs, and running tests. It's powered by OpenAI’s GPT-5.3-Codex models and is used by over 4 million people weekly. This mobile integration puts Codex in direct competition with Claude Code, which launched mobile access in late 2025. This update allows more developers to manage their coding projects on the go, making AI coding tools more accessible than ever.