Codex is Here: OpenAI’s Cloud-Based Programming Tool for Developers
OpenAI has introduced Codex , a cloud-powered software engineering agent capable of handling multiple development tasks simultaneously. Built on the new codex-1 model — a specialized version of OpenAI’s o3 fine-tuned with reinforcement learning on real-world coding challenges — Codex operates autonomously in an isolated environment, preloaded with the user’s codebase.
This unique setup enables Codex to carry out various tasks at once, such as developing new features, debugging, answering code-related queries, and submitting pull requests for review. According to OpenAI, most tasks are completed within 1–30 minutes, depending on complexity, and the system can provide verification logs upon completion.
Currently, Codex is accessible via ChatGPT Pro, Enterprise, and Team plans, with support for Plus and Edu tiers coming soon. During its research preview phase, access is free for the coming weeks, though future use will include rate limits and flexible pricing.
Codex does have limitations — it doesn’t support image inputs, cannot be adjusted mid-task, and isn’t suited for long-running or highly complex operations.
Alongside Codex, OpenAI also updated Codex CLI , an open-source, terminal-based coding agent. It now includes a lighter, optimized version of o4-mini , designed for faster performance in code Q&A and editing. Users can now log into their ChatGPT accounts directly from the CLI, eliminating manual API key setups. Plus and Pro users receive $5 and $50 in free API credits respectively for one month.