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Is Codex Free? GPT-5.6, ChatGPT Work, CLI, Credits, and API
Yes—Codex is included in ChatGPT Free. Free and Go use GPT-5.6 Terra in Work and Codex; higher tiers add model choice and usage, while API keys are billed separately.
Clarify the spend threshold before you commit. Use this page when the core product is familiar and the real question is whether to stay free, upgrade, or switch pricing tracks.
Editorial guide
Guide
Start with the spend threshold and the conditions that change the pricing decision.
Short answer: Codex is included in ChatGPT Free
Codex is included in ChatGPT Free, and the new ChatGPT desktop app exposes Chat, Work, and Codex on every plan. Free and Go access GPT-5.6 Terra; usage limits are lower than Plus and higher tiers. API-key workflows remain separately billed.
ChatGPT Work and Codex share the same agentic usage and credit structure when available on a plan. API-key sessions use standard OpenAI API pricing instead and do not consume the ChatGPT allowance.
Codex access routes at a glance
Route | What it can cover | Cost boundary |
|---|---|---|
ChatGPT Free | $0 entry access for quick tasks with GPT-5.6 Terra | Included usage is limited and plan-specific. |
ChatGPT Go, Plus, or Pro | More app-side access and higher plan limits | Still not the same as API billing. |
Codex CLI sign-in | Developer workflow access tied to account route | Authentication and product access are separate from API-key spend. |
Business or team route | Workspace governance and team usage | Seat, admin, and task limits need separate review. |
OpenAI API | Programmatic model calls | Metered API billing is a different budget. |
Free Codex access vs paid plans
Codex is included across Free, Go, Plus, Pro, Business, Edu, and Enterprise. Free and Go use GPT-5.6 Terra; Plus, Pro, Business, and Enterprise can choose Sol, Terra, or Luna, with plan-specific limits.
If the buyer is choosing specifically for Codex, compare plan route, task limits, model access, and whether the workflow is interactive, agentic, or API-driven.
CLI, cloud tasks, and credits
ChatGPT desktop, CLI, and IDE can use ChatGPT sign-in for included access or an API key for separate billing. Codex cloud requires ChatGPT sign-in. A free user can start locally and still hit plan limits once Codex becomes regular work.
For heavier use, the buyer should compare task limits and pricing rather than treating "free" as the only decision.
Codex credits are not OpenAI API billing
OpenAI API usage should be planned as a developer budget. A ChatGPT plan or Codex product route can be useful for interactive coding work, but API keys, backend calls, and automation need their own billing check.
Evidence boundary
Official sources
Editorial guidance grounded in official product sources.
FAQ
Common questions
Can I use Codex for free?
Yes. Codex is included in ChatGPT Free, with plan-specific usage limits.
Does ChatGPT Go include Codex?
Yes. ChatGPT Go includes Codex and uses GPT-5.6 Terra for Work and Codex.
Is Codex CLI free?
The CLI is free to install. ChatGPT Free sign-in provides limited included usage; API-key sign-in is billed at standard API rates.
Are Codex credits the same as OpenAI API credits?
No. Eligible ChatGPT Work and Codex usage can share plan-side credits, but those credits do not pay API invoices. API-key usage remains separately billed.
When should a team pay for Codex instead of staying free?
Pay when task volume, workspace ownership, governance, admin controls, or predictable coding-agent capacity matters more than a free starting route.
Is Codex free if I bring an API key?
No. Bringing an API key moves cost to the API billing account behind that key; it does not make API-backed usage free.
Next steps
Take the next buying step
Use these next pages to confirm the plan, tool, or alternate route that fits once the spend boundary is clear.