This comparison has an unusual shape, because Talyn runs Codex. Sign in with ChatGPT and Talyn runs Codex on your own Plus or Pro plan. The model and the vendor are the same. The questions are where you run it, and what happens once the pull request opens.
What Codex cloud does
From OpenAI's own documentation, read on 10 November 2026:
- Runs tasks in isolated cloud environments, which continue while you do something else.
- The docs page says you start cloud work from the web, mobile, the desktop app and the Codex CLI.
- Produces pull requests ready for review: you inspect the summary and diff, ask for a follow-up, or open the pull request when it is ready.
- Network access has options: all public internet, package manager domains only, or extra allowed domains.
In September, we also read that Codex cloud launches from GitHub issues and pull requests, GitLab merge requests (beta), Linear and Slack. The current docs page does not list these. We have not re-checked them, so treat them as last reported.
It is a good product with more entry points than Talyn has.
We found no documented way to create a Codex cloud task from a backend (checked 10 November 2026). The docs link a Codex SDK and an App Server, and we did not find that either one creates cloud tasks. If one does, this paragraph is wrong, so tell us. Talyn runs Codex in its own sandboxes on your subscription and does not drive Codex cloud.
What Talyn adds
A session per task. Each session has its own branch, Codex agent, sandbox, diff, terminal and run scripts. Run many at once, and they never touch each other's files. Send messages while the agent works, start your app, or roll the files back to an earlier message.
Threads. One conversation with a goal that starts a session on every repository that needs a change, and tracks each one.
Past the pull request. One button opens the pull request. The same button then fixes failing checks, resolves conflicts and merges. A merge queue lands ready pull requests in order and sends an agent when one breaks.
Your pull requests as a set. The dashboard lists every pull request you own or need to review, blocked ones first. That includes ones from teammates and Dependabot. A fix pushes to the existing branch, so the review history stays.
Work that starts without you. GitHub automations run on pull request events with the app closed. Scheduled automations run a prompt on a cron schedule. Both start Codex runs from our backend.
Code review in the app. Several reviewers read the change, then a check drops what it cannot back up. Findings reach GitHub only if you post them.
Both vendors in one app. Connect Claude and ChatGPT, and pick per session. The model you pick decides the vendor and the credential.
How the sandbox differs
Codex cloud runs in OpenAI's environment. Talyn runs Codex in a Firecracker microVM on our own hardware. A proxy outside the machine adds your ChatGPT credential, so no token is inside the box that runs your repository's code. Talyn builds an image of your repository with its setup done, and a sandbox sleeps after 10 idle minutes.
Each session has an Internet on / Internet off switch. You set the default for new sessions in Settings. Fix runs and code reviews reach only the repository and the agent's API, and scheduled automations have their own switch. You can also connect MCP servers (Linear, Sentry, Supabase, your own). Talyn holds their keys outside the sandbox.
What Talyn does not do
- GitHub only. OpenAI reported GitLab support (beta) in September.
- No ChatGPT-native surface, and no GitHub issue or Linear trigger.
- Nothing to do with ChatGPT conversations. Talyn is a separate app.
- Finite hardware. Talyn's sandboxes run on our own machines. OpenAI's capacity is not our capacity.
- Talyn costs money. Free with 10 box-hours a month, or $40/month for 200 box-hours and every box size, with credits above that. Codex cloud ran on your ChatGPT plan when we last confirmed it. The current docs page does not say which plans include it.
Which one
Use Codex cloud if dispatching is what you want and OpenAI's surfaces are where you already are (ChatGPT on the web, mobile or desktop, or the CLI).
Use Talyn if you want the same Codex subscription running many sessions at once, each with its own diff and terminal, and each pull request carried through to merged. You can also run Claude on some of them, with nothing else to change.