OpenAI has expanded its AI coding capabilities to mobile devices by integrating Codex into the ChatGPT iOS app, as announced by OpenAI President Greg Brockman on May 20, 2025.
Codex, which was initially launched as a research preview for desktop users on May 16, represents a significant advancement in AI-assisted software development. Unlike traditional code completion tools, Codex functions as a full-fledged software engineering agent capable of writing features, fixing bugs, answering questions about codebases, and proposing pull requests.
The iOS integration is powered by codex-1, a specialized version of OpenAI's o3 AI reasoning model that has been optimized specifically for programming tasks. According to OpenAI, codex-1 produces cleaner code than the standard o3 model, adheres more precisely to instructions, and can iteratively run tests on its code until achieving passing results. Each coding task runs in its own secure, sandboxed cloud environment, with no access to the broader internet or external APIs for security reasons.
The mobile expansion has already generated significant interest beyond the developer community. Following the iOS launch announcement, AI-focused cryptocurrencies experienced notable price movements, with Fetch.ai (FET) rising 3.2% to $1.75 and SingularityNET (AGIX) gaining 2.8% to $0.62 on major exchanges within hours of the news.
Currently, Codex is available to ChatGPT Pro, Enterprise, and Team subscribers, with plans to expand access to ChatGPT Plus and Edu users soon. During the initial research preview period, OpenAI is providing "generous access" at no additional cost, though rate limits and flexible pricing options for additional usage are expected to be implemented in the coming weeks.
This release reflects OpenAI's broader strategy to eventually support both real-time AI coding assistants and asynchronous agent workflows. While Codex currently connects with GitHub and is accessible from ChatGPT on both desktop and now iOS, OpenAI envisions deeper integrations in the future, including support for assigning tasks from Codex CLI, ChatGPT Desktop, and tools such as issue trackers or CI systems.