OpenAI Codex review

OpenAI Codex is bundled with ChatGPT, which makes it the easiest agent to try if you already subscribe. The free plan and Go at $8 a month run GPT-6 Luna at standard speed in the desktop app, which suits lighter tasks. Plus at $20 a month is where Codex becomes a full product: it runs on the web, in the CLI, in the IDE extension and on iOS, adds automatic code review and Slack, and lets you extend usage with ChatGPT credits. OpenAI publishes estimates rather than fixed limits, for example 15 to 160 local messages per five hours on GPT-6.1 Sol for Plus, and notes that model choice, context and tool use all affect usage. Pro plans at $100, $200 or $500 a month currently have no five-hour limit. Teams that want Codex in CI can use an API key instead, paying API rates but losing the cloud integrations.

Who it is for

ChatGPT subscribers who want a coding agent with cloud tasks and automatic code review on the plan they already pay for.

Price

Free plan; Go $8 per month; Plus $20 per month; Pro from $100 per month.

Use Codex for lightweight coding tasks. $8 /month
Quoted from the vendor pricing page on November 6, 2026.

Key features

• Included in ChatGPT Free, Go, Plus, Pro, Business, Edu and Enterprise
• Codex on the web, in the CLI, in the IDE extension and on iOS from Plus
• Automatic code review and a Slack integration from Plus
• Extra usage through ChatGPT credits
• API key option for CI and shared automation

Strengths and weaknesses

• Strength: Go starts at $8 a month, the joint lowest paid entry price here
• Strength: Plus covers cloud features such as automatic code review
• Strength: Pro plans have no five-hour limit
• Weakness: Go and Free are limited to GPT-6 Luna in the desktop app
• Weakness: Usage per message varies with model, context and task, so limits are hard to predict
• Weakness: API key mode drops cloud features such as GitHub code review and Slack

Key facts

• Free plan: Yes, quick coding tasks with GPT-6 Luna
• Go: $8 per month
• Plus: $20 per month
• Pro: $100, $200 or $500 per month
• Plus local messages: 15 to 160 per 5 hours on GPT-6.1 Sol

Where it ranks

OpenAI Codex is No. 3 in our Best AI Coding Assistants verdict.