Coding · Updated 2026-10-25
OpenAI Codex — what it is actually for
Codex is OpenAI's software-engineering agent. It runs in ChatGPT, a command-line tool, IDE extensions, and cloud tasks, and can be used with a ChatGPT plan or an API key.
Short answer: use OpenAI Codex when you need delegating coding tasks to a cloud or local agent. It is a subscription + usage-based api service from OpenAI; the official pricing source is linked below.
- Vendor
- OpenAI
- Category
- Coding
- Pricing model
- Subscription + usage-based API
- Free option
- Yes, with limits. The Free ChatGPT plan includes limited Codex access.
What OpenAI Codex is used for
- Delegating coding tasks to a cloud or local agent
- CLI and IDE code changes with review
- Automating repository work with an API key
Source: official product page and official documentation.
Who OpenAI Codex is for
- Existing ChatGPT subscribers
- Teams that want both cloud and local coding agents
- Developers automating repository work through an API key
Source: official documentation.
Who it is not for
- Buyers who want a fixed-price coding product with no plan limits
- Deployments that must run fully offline
Source: documented plans, limits, and deployment model on the official product page.
Pricing
- Codex CLI is open source. Usage through ChatGPT is included in Free, Go, Plus, Pro, Business, and Enterprise plans with plan-specific limits.Source: chatgpt.com
- API-key runs are billed at standard OpenAI token rates.Source: openai.com
- Paid ChatGPT plans can buy additional credits after reaching included limits according to the Codex pricing documentation.Source: chatgpt.com
Codex has no separate standalone subscription. The cost depends on the ChatGPT plan or API token usage.
Full pricing page: https://chatgpt.com/pricing
Alternatives to OpenAI Codex
- Claude Code — Agentic coding tool for terminal and IDE workflows, included in paid Claude plans.
- GitHub Copilot — AI coding assistant across GitHub, IDEs, the CLI, and pull-request review.
- Cursor — AI-first code editor and agent platform with pooled usage plans.
Official sources
OpenAI Codex FAQ
Is Codex free?
Codex CLI is open source, and the Free ChatGPT plan includes limited Codex access. Higher limits require a paid ChatGPT plan or API billing.
Does Codex require a ChatGPT subscription?
No. You can use an API key instead, but API runs are billed at token rates.
What is the difference between Codex and ChatGPT?
ChatGPT is a general assistant. Codex is the coding agent that can run in the terminal, IDE, and cloud and work directly on repositories.