Best suited for: People who want to create, change, test, and maintain application code with AI assistance, including work on existing projects.
What is Codex?
Codex is OpenAI's AI coding agent. It can read project code, edit files, support debugging, and help test changes through supported interfaces such as the desktop app, command line, and IDE integrations. Codex Cloud requires an eligible paid plan and account; it is not included with Free or Go.
Unlike an integrated AI app builder, Codex primarily supports the development process. Creating code does not automatically provide a public website, managed database, app-store listing, or ongoing hosting.
Typical uses
- Updating an existing web application
- Adding interfaces, APIs, or data-processing features
- Investigating bugs and writing tests
- Working in projects that already have a hosting environment
Try it in three steps
- Describe one concrete user journey, including inputs and expected results.
- Ask Codex to implement one small feature; review the changed files and test results.
- Test it on the target devices and arrange deployment through an appropriate external service when needed.
Pricing
Codex has limited access on ChatGPT Free and Go, with additional access on paid plans. As of November 11, 2026, ChatGPT Plus is listed at US$20/month, and Pro starts at US$100/month. Limits and cloud eligibility vary by plan; check official pricing before subscribing.
ChatGPT pricing · Official pricing guide · Codex plan availability
Publishing and custom domains
Codex can help produce application code, but deployment usually requires external hosting, build tools, and potentially a database. Custom-domain support depends on the hosting provider. Native iOS and Android releases require their own development and store-review workflows.
Points to check
AI-generated changes still need testing, security review, access-control checks, dependency updates, and a maintenance plan. Being AI-assisted does not mean being maintenance-free.
Related tools
- Base44: an integrated AI web-app builder
- Claude Code: code editing and testing
- ChatGPT Work + Sites: lightweight web-app creation and publishing
Official Codex website — standard editorial link; no affiliate commission is claimed.
Official sources reviewed: November 11, 2026. Always confirm current price, limits, and deployment requirements.