Using OpenAI Codex from the ChatGPT Mobile App

Codex on mobile lets you continue coding tasks away from your desk. In the ChatGPT iOS app, open Codex to connect to a Mac or Windows host, or select a published cloud environment for cloud work. Older app versions may label the host connection Remote.

This guide covers the connected-computer workflow: the phone sends instructions and displays results while the host supplies project files and development tools.

I trust Codex as a second agent, and on a phone I limit that trust to steering and review decisions that fit the screen.

Phone access is one part of the decision; our coding assistant recommendations compare the underlying tools you will be supervising.

The Codex overview explains the product and review workflow behind these remote sessions.

How Does Codex Remote Access Work?

Codex Remote gives you access to coding work running on a connected computer. The mobile app can start a new chat in a host project or continue an existing one. It can send follow-up instructions, answer Codex's questions, approve actions, read outputs, and move between connected hosts.

For connected-computer work on iOS, open Codex in ChatGPT, or Remote if your app still uses that label. It opens supported chats running on a connected computer. Those remote chats remain separate from ordinary mobile or web chat history.

The host supplies the files, terminal, credentials, plugins, browser setup, permissions, and other local tools. The phone displays that session and sends your choices back. This split explains why the computer must remain awake and why you should secure both devices.

Check the Host and Account

Set up the desktop side first. Install the latest ChatGPT desktop app on a Mac or Windows computer, sign in, open Codex, and confirm that a small local project works. If you cannot complete a normal desktop task, pairing a phone adds another place to troubleshoot without fixing the base problem.

• Use the latest ChatGPT desktop app on the host.
• Use the latest ChatGPT iOS app for the host-connection workflow documented here.
• Sign into the same account and workspace on both devices.
• Finish any required passkey, multi-factor, or single sign-on step.
• Ask the workspace owner whether Remote Control is allowed on managed accounts.

Host access requires the same account and workspace on both devices, an online host, and any required workspace permission. Cloud tasks use a separate environment and do not depend on keeping your personal computer awake.

Pair Your Phone and Host

1. On the host, open the ChatGPT desktop app and open Settings > Connections > Control this Mac or PC, then choose Set up or Add.
2. Enable remote access for that computer when the app asks.
3. Scan the displayed QR code with the phone you want to pair.
4. Finish the connection in ChatGPT with the same account and workspace.
5. Complete any extra sign-in check required by the workspace.
6. Open Codex (or the older Remote entry) on the phone and confirm that the host appears.

The QR code pairs one controller with one host. Repeat the flow for another phone or computer. OpenAI also says older connections that had not been used since June 8, 2026 may need to be paired again after both apps are updated.

In the host app, open Settings > Connections after pairing. Check the device list, decide whether the computer should stay awake while plugged in, and leave Computer Use or the Chrome extension off unless the task needs them.

Start or Resume a Task

Open Codex on the phone and choose the paired host. You can continue a running chat or start a new chat inside one of that host's projects. The new task uses the chosen computer's project folder and local access. The phone stores neither the files nor the working copy.

A mobile prompt should be easier to verify than to type. Name the task, path, stopping point, and check. If the job needs a long spec, write it in the repository or begin at the desk. A few thumb-typed lines are a poor place to define a migration, permission policy, or product requirement.

The host list matters when you use more than one computer. Confirm the machine and project before you send the prompt. A task aimed at a personal laptop may have different files, credentials, and branch state from a similar project on an office workstation.

Steer and Approve from Mobile

Codex can pause to ask a question or request approval. Remote surfaces that prompt on the phone. Read the full action, the project, and any shown command before choosing. Mobile access changes where you approve the action; it does not turn a risky command into a routine one.

Prompt	Phone Fit	Response
Run focused tests	Usually good	Check command
Read another file	Often good	Check path
Add a package	Poor	Wait for desk
Change auth or data	Poor	Review in full

Use steering messages to correct direction before more files change. "Stop editing and show the current diff" is a valid response. So is "return to the original file list." If the reason for a command does not fit on the screen or the change has wider effects, leave the task paused.

Review Progress Without Merging

Remote can show terminal output, diffs, tests, screenshots, project context, and plugin results from the host. This is enough to answer a progress question: Is the test still failing? Did Codex touch the wrong folder? Does the screenshot show the requested state?

Final review still belongs on a larger screen. A phone diff can hide the relation between several files, and a screenshot cannot prove keyboard use, error handling, or network behavior. Use mobile review to continue, pause, or redirect the task.

• Continue: the file list and focused check match the task.
• Pause: the diff is too large to read without context.
• Redirect: the agent moved beyond the named scope.
• Reject: the action can delete data or widen access.

Save the merge decision for a full screen. Read every changed file, rerun the repository's required checks, and use the approved browser or device flow for user-interface work. Mobile convenience can shorten idle time while the release gate stays unchanged.

A completion notification prompts you to inspect the result. Confirm that the final command passed, the diff stayed in scope, and another task did not change the same checkout.

Manage Connections and Security

Remote reaches the host's projects and credentials through your signed-in account, so account security matters. Use the workspace's required authentication and lock the phone. On a shared or managed device, do not leave a remote session open where another person can approve actions.

Review connections in the desktop app after replacing a phone, leaving a team, or retiring a computer. Remove devices you no longer use. Turn off remote access when the host should not accept controllers, and close the desktop app to disconnect remote access. This does not mean every cloud task is canceled; stop a task explicitly in its own controls when cancellation is the goal.

Remote keeps the source tree on the host. The phone can still display code, terminal text, screenshots, and diffs. Treat what appears on screen as project data. Avoid opening a client repository over a public display or while screen sharing with the wrong audience.

Know What Needs a Desk

The phone cannot replace a working development setup. The host must provide the repository, tools, and runtime. Remote also stops when the host sleeps, loses its connection, signs out, or closes the desktop app. Keep an always-on host only when the access and power trade-off is deliberate.

Use the desk for the parts that set authority or decide what ships: changing permissions, adding plugins, reviewing large diffs, resolving merge conflicts, inspecting browser behavior, approving migrations, and merging a pull request. The Codex desktop guide covers the first local task and review loop.

What Belongs on the Phone

Codex Remote fits the waiting and steering parts of agent work: checking progress, answering a narrow question, approving a known test command, or stopping a task that has drifted. It saves a trip back to the desk without moving the repository or development tools onto the phone.

Keep final code review and release decisions on a full screen. With that boundary, Remote extends a desktop Codex workflow while the full review evidence stays at the desk.

FAQ

Is Codex a full mobile coding app?

Codex on mobile controls work on a connected computer or cloud environment rather than providing a full local development environment on your phone. For host-backed work, the phone controls the session while the computer retains the files and tools.

Can Windows host a Codex Remote session?

Windows can host a Codex Remote session. OpenAI's Remote documentation lists the ChatGPT desktop app on macOS and Windows as supported hosts. Availability can vary during rollout, and Enterprise workspaces may need an administrator to enable Remote Control before a phone can connect to a Windows or Mac host.

Does the host have to stay awake?

A computer hosting a Codex Remote session must stay awake, online, signed into the same account and workspace, and running the ChatGPT desktop app. Remote access stops if that computer sleeps, loses its network connection, or closes the app. The host settings may offer a keep-awake option while it is plugged in.

Can I pair more than one host?

Codex Remote supports pairing with multiple hosts and can switch between connected hosts and chats. Pair each phone or supported desktop controller with each host you want it to control. Name and review those connections in the desktop app, then remove old devices so the list still reflects the computers and phones you use.