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How-to3 min read

The Codex app: where to get it now, and running Codex next to other agents

OpenAI's Codex desktop app now lives inside the ChatGPT desktop app. Where to get Codex on each platform, and how to run it next to Claude Code in Mirasim.

A new Mirasim session with Codex selected in the composerA new Mirasim session with Codex selected in the composer

The short answer

OpenAI's desktop app for Codex is the ChatGPT desktop app. Download ChatGPT for macOS or Windows (Linux is in preview), sign in with your ChatGPT account, and choose Codex when you start. If you already use the Codex CLI on macOS or Windows, codex app opens it, or starts the installer when it isn't installed yet.

WhereOpenAI's way
DesktopThe ChatGPT desktop app: macOS, Windows, Linux (preview)
TerminalThe open-source Codex CLI (Apache-2.0)
EditorThe Codex IDE extension for VS Code, Cursor and Windsurf
Browserchatgpt.com/codex, running tasks in Codex Cloud
PhoneCodex in the ChatGPT app for iOS and Android

Codex on Linux

The ChatGPT desktop app for Linux is a preview. It supports Ubuntu 24.04 and 26.04 LTS, Debian 13, Fedora 43 and 44, and Arch Linux, on x64 and ARM64, as a .deb, an .rpm or an install script for Arch. On other distributions, or on a server without a desktop, use the Codex CLI.

Install the Codex CLI

macOS, Linux
curl -fsSL https://chatgpt.com/codex/install.sh | sh
Windows
powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"
npm
npm install -g @openai/codex
Homebrew
brew install --cask codex
Binaries
The latest GitHub Release of openai/codex has a build for each platform

Then run codex in your project and sign in with your ChatGPT account or an API key. In Mirasim, Get started can install Codex for you and suggests it if you have a ChatGPT account.

Running Codex in Mirasim

Next to Claude Code
Codex in one pane, Claude Code or Kimi Code in the next
Switch and keep the thread
Move a session to another agent and the conversation comes along
On your phone
Follow and answer Codex away from your desk
With your team
Several people in one Codex session

Mirasim is a desktop app for macOS, Windows and Linux that runs the Codex CLI itself, on your ChatGPT sign-in, an API key, or Mirasim credit. It is not an OpenAI app.

Article · Claude Code vs Codex: how they differ, and using both → Claude Code and Codex compared, and running both.

Questions

Is there a separate Codex desktop app?
OpenAI's desktop experience for Codex is the ChatGPT desktop app, where you choose Codex. codex app in the CLI opens it.
Does the Codex app work on Linux?
The ChatGPT desktop app for Linux is in preview for Ubuntu, Debian, Fedora and Arch. The Codex CLI and Mirasim also run on Linux.
Is Mirasim the official Codex app?
No. Mirasim is a separate desktop app that runs the Codex CLI alongside Claude Code and eight other agents.
Can I use my ChatGPT plan with Codex in Mirasim?
Yes, sign in to Codex with your ChatGPT account. A personal subscription is for its owner only, so a session your team shares runs on a shared key or space credit.

Article · Codex on your phone: the ChatGPT app, and other ways → Codex on your phone: the ChatGPT app, and other ways.

Sources

Checked against OpenAI's documentation on November 8, 2026: learn.chatgpt.com/docs/app, /docs/linux/linux-app and /docs/developer-commands, and the README at github.com/openai/codex. OpenAI changes these often, so check those pages for the latest.

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