Sign in with ChatGPT: use your plan in Devin, Warp and T3
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Sign in with ChatGPT lets you log in to other tools with your ChatGPT account and, on Plus or Pro, let those tools run AI requests on your ChatGPT plan instead of an API key. At DevDay 2026, OpenAI announced plan usage across 16 participating tools, including Devin, Notion, Vercel, T3, OpenClaw and Dactyl. The Sign in with ChatGPT documentation lists the tools and the controls, and the key point for Codex users is that this usage comes out of the same allowance Codex uses.
The identity part is available globally. Plan usage is limited to Plus and Pro subscribers in participating tools.
Which tools support Sign in with ChatGPT?
The documentation splits supported apps into three groups. The first two can use your plan for AI requests. The third only uses ChatGPT for sign-in.
| Group | Apps |
|---|---|
| Commercial apps with plan usage | Amp Code, Conductor, Dactyl, Devin, Hermes Agent, Hyperagent, Kilo Code, Lovable (coming soon), Notion, Vercel, Vorflux, Warp |
| Open-source apps with plan usage | OpenClaw, OpenCode, Pi, T3 |
| Sign-in only | Airtable, Canva, GitLab, HubSpot, Supabase |
Lovable is marked coming soon. The help article adds that all users can connect supported open-source tools, while eligible commercial tools need Plus or Pro.
How do you use your ChatGPT plan in other apps?
In a supported tool, pick Sign in with ChatGPT. You then review two separate permissions.
The first is sign-in. The app receives your name, email address and profile picture.
The second is the Use your ChatGPT plan permission. It needs its own consent. Once you allow it, eligible AI requests from that app count toward your ChatGPT Work and Codex usage. No OpenAI API key is created or shared, and the app gets no access to your ChatGPT conversations or memories.
That second point matters if you currently paste API keys into tool settings. With plan usage there is no key to rotate or leak, and your plan limits bound the spend.
How do you set a weekly limit per app?
Open Settings > Usage in ChatGPT. For each connected app, open the percentage menu and set its weekly limit as a percentage of your total weekly plan usage.
Two details from the docs change how you should read that number:
- The limit is a cap, not a separate allowance or a reserved part of your plan. Setting an app to a share does not protect that share for it.
- Connected app usage counts toward your existing plan limits. It adds no new allowance.
A separate setting, Allow other apps to use credits after reaching your usage limit, decides what happens when the plan runs out. It is off by default. Leave it off until you know what a normal week costs.
To remove an app entirely, go to Settings > Security and login > Sign in with ChatGPT, select the app and choose Disconnect.
Check your Codex budget before you connect a second agent
Here is the practical risk. Codex and a connected tool such as Devin or Warp draw on the same weekly plan usage. A long unattended run in one tool can leave less for Codex on the day you need it.
A simple setup for a developer who uses Codex daily and one other agent:
- Connect the second tool with Sign in with ChatGPT and allow plan usage.
- In Settings > Usage, give it a weekly cap you can live without, for example a quarter of your plan.
- Keep the credits setting off.
- Run a normal week, then check Settings > Usage and compare the app's share with the value you got from it.
- Raise or lower the cap, or disconnect the app, based on that review.
Caps do not reserve anything for Codex, so the check in step 4 is the real control. Write your cap next to your other Codex rules, for example in the notes your team keeps beside AGENTS.md, so teammates know the default. If your team wants to agree defaults like this together, our training for Codex teams is one place to do it.
Which plan should you be on?
Plan usage needs Plus or Pro. The Pro tiers help article lists Pro 100 at $100 a month, Pro 200 at $200 a month and Pro 500 at $500 a month. Pro 500 has 25 times the Plus allowance and is the only Pro tier that includes Ultrafast. It also says credits cover Codex and ChatGPT Work. If connected tools start to crowd out Codex, compare the cost of a higher tier with the cost of those credits before you enable either.
Adding Sign in with ChatGPT to your own app
For builders, the developer docs at developers.openai.com/siwc describe three integration paths: a website, a ChatGPT plugin, and plan usage in open-source apps. For a website you request an OAuth client first, and the client ID typically starts with oaiapp_. The flow is OAuth 2.0 Authorization Code with PKCE and OpenID Connect, using the openid, profile and email scopes. Your backend verifies the ID token and keys the user on the sub claim with the issuer and client ID.
Plan usage through sign-in has its own flow, documented for open-source apps. The docs we read do not describe how a commercial app joins the plan-usage list, pricing for developers, or rate limits. Treat those as not documented yet.
Pick one tool this week, connect it, set its cap in Settings > Usage, and review the numbers after seven days.