boxes.dev vs Codex

At a glance

As of September 2026. This page compares boxes.dev with Codex cloud, where OpenAI runs Codex chats in its own containers.

What the cloud machine starts from

Codex cloud starts each chat from a fresh checkout of your repository, and boxes.dev starts from a copy of a machine where your app already runs.

Each Codex cloud chat starts a container with your repository checked out at the branch or commit you choose, in a default image with common languages and tools. Cloud chats count toward your ChatGPT plan's usage allowance, with no separate charge for the container. Codex installs dependencies for common package managers, and a setup script can add anything else. Secrets are available only to the setup script and are removed before the agent starts working, and the agent's internet access is off unless you allow it.

boxes.dev first sets up your full development environment on a cloud machine called the Template box, with the tools, databases, services, and data your app needs, so an agent can run the app and test its changes end to end. A setup agent can port the environment from your laptop, including the files, local data, agent settings, and skills you choose to upload, or build it from a GitHub repository. boxes.dev then saves the Template box as a snapshot, and every task runs on its own devbox, a full, isolated copy of that machine. A maintenance script can keep the Template box current as your code changes, running on a schedule or when files such as a lockfile change, and each successful run saves a new snapshot.

You'd never let an engineer ship code they hadn't run, and a full environment holds the agent to the same standard. On a boxes.dev devbox, the agent runs your app and tests its changes in the browser as it builds, and it reproduces bugs in the real app to find the root cause instead of guessing from the code, so it writes better code and makes fewer mistakes. It can also take screenshots and record video for you to review, so you can hand it most repetitive manual testing.

What's kept between tasks

A boxes.dev devbox keeps its running programs through sleep and stays until you delete it, while a Codex cloud chat leaves behind its answer and diff.

Codex caches container state for up to 12 hours so new chats and follow-ups start faster. Each chat leaves behind its answer and diff, which you can turn into a pull request.

A boxes.dev devbox sleeps when nobody is using it, and an agent that is still working keeps it awake. Sleep keeps the machine's files and memory, so dev servers, databases, and terminal sessions resume where they left off when it wakes. You can come back the next day to the same files, branches, and data.

Working in the machine

In a Codex cloud chat, Codex runs the commands in the container, and on boxes.dev, you can also work in the devbox yourself.

In a cloud chat, you can watch the task logs, then review the summary and diff, ask for follow-up changes, or open a pull request. The desktop app's integrated terminal works in projects on your computer.

On boxes.dev, you can open a terminal on the devbox, edit its files, and run your app alongside the agent, with the tools listed under What comes with every boxes.dev devbox, over SSH, or in VS Code or a JetBrains IDE with dvb ide.

Reaching the running app

On boxes.dev, you and the agent can both use the app running on a devbox, and the ChatGPT desktop app previews apps running on your computer.

The ChatGPT desktop app's built-in browser shows you and Codex web apps running on your computer, and you can comment on the page for Codex to address.

Each boxes.dev devbox runs a browser that you and the agent share, so you can watch the agent test the app, click through it yourself, or comment on page elements to show the agent what to change. Ports forwards the app to the same localhost port on your laptop, a public link shares a devbox's running app with anyone, and a Project URL gives your project one stable public address that you can point at any devbox, which suits OAuth callbacks and webhooks.

Working with your team

Both bring agents into Slack, and boxes.dev also lets teammates you allow send follow-ups to your conversation and start work in your project, with your access.

Mentioning @Codex in a Slack channel or thread starts a cloud chat that can read the thread's earlier messages, and Codex posts its result in the thread. In the ChatGPT desktop app for macOS, you can share a read-only snapshot of a local Codex thread by link. On Business and Enterprise, everyone with access to a cloud environment shares its cached container.

Each boxes.dev devbox belongs to one person and works with their access, such as their GitHub login and cloud credentials. Anyone who can prompt its agent could act with that access, so in the app, teammates get read-only access to your work. You can share a thread as a link, and a team admin can let teammates read every thread that isn't marked private and browse each other's projects in a Team workbench. Teammates can't send prompts, open your terminal, or control your devbox.

In Slack, mentioning @boxes.dev in a thread starts Codex or Claude Code on a new devbox, and later mentions in that thread send follow-ups to the same conversation. By default, only you can start work in your project from Slack or follow up on it. If you allow teammates, they can also start work there with @boxes.dev @YourName and send follow-ups, and their requests run with your access and usage. boxes.dev sends you a DM with links to each task a teammate starts, and commits can link to the thread that produced them.

What comes with every boxes.dev devbox

The boxes.dev desktop app opens the same set of tools for whichever devbox you select:

• Terminal, with tabs that keep running after you close the app.
• Files, a file browser and editor with search across the workspace.
• Git/Review, for branch history and diffs, where comments on changed lines go to the agent together as one message.
• Browser, the browser on the devbox that you and the agent share.
• Ports, for the forwarding, .localhost addresses, and public links described above.
• Activity, which shows the processes using the machine's CPU and memory.

AWS, Tailscale, and the MCP servers and Codex plugins you add for the project reach every devbox, and agents can leave each other notes in a shared /project folder. You can branch a conversation onto a new devbox that starts with the current files, including uncommitted work.

Where Codex shines

• One command from your terminal. codex cloud exec submits a task to a cloud environment, and codex apply brings a cloud chat's latest diff into your local repository.
• Automatic pull request reviews. Codex can review every new GitHub pull request, flag only high-priority issues, and follow review rules from AGENTS.md.
• Codex Security. A security agent finds, confirms, and helps fix vulnerabilities, from the desktop app, the terminal, an SDK, or connected GitHub repositories.

Pricing

As of September 2026.

A box-hour is one default devbox awake for an hour, and sleeping devboxes don't use any. On Starter, 40 box-hours works out to about two hours of devbox time each working day, and Pro's 250 to about twelve, spread across as many as ten devboxes at once. Your ChatGPT plan covers Codex's usage on boxes.dev, and the boxes.dev plan covers the machines. See Plans, seats, and box-hours.

OpenAI's pricing page says that weekly limits may also apply to the plan's usage allowance, and that Business costs $20 per user each month when billed annually. See Codex pricing.

Using both

We recommend using both. Codex is a great agent, and boxes.dev runs the real Codex CLI on every devbox with your ChatGPT subscription, so your AGENTS.md, skills, and settings work the same way in both places. You can keep Codex's automatic reviews on your pull requests and @Codex for quick tasks from Slack, and use boxes.dev for tasks that need your full environment, a terminal, or the running app.

Frequently asked questions

Is boxes.dev affiliated with OpenAI?

No. boxes.dev is an independent product and isn't affiliated with or endorsed by OpenAI.

Can I use my ChatGPT plan with boxes.dev?

Yes. Sign in with ChatGPT to connect Codex, or use an API key. Codex's usage on boxes.dev counts toward your ChatGPT plan, and boxes.dev charges only for machine time. See Connect Codex and Claude.

Do AGENTS.md, skills, and MCP servers work?

Yes. Codex on a devbox reads your repository's AGENTS.md, and project setup can copy agent settings, skills, and MCP definitions from your computer. Plugins that Codex syncs to your account work on devboxes too.

Sources

• Codex: Codex cloud, cloud environments, agent internet access, Codex CLI commands, GitHub code review, Slack, Linear, integrated terminal, browser, sharing threads, subagents, Codex Security, and pricing.
• boxes.dev: How boxes.dev works, Update your Template box and snapshots, Startup, teardown, and maintenance, Sleep, wake, and recover a devbox, Review a page with your agent, Preview your app, Project URLs, Shared project storage, Use the agent's terminal view, Install agent plugins, Organize and share threads, Team access and roles, Commit, push, and open a pull request, Install and use the CLI, Work from Slack, Work from Linear, Use boxes.dev on your phone, and Plans, seats, and box-hours.