OpenAI Oauth for subscriptions?

[frankyw]

Hey Matt,

I was wondering if there is a way to use an existing ChatGPT subscription (oauth) rather than an API key for OpenAI? It would nice to use an existing ChatGPT subscription with Busbar.

I know some tools print a code to the log or console that you can enter on the OpenAI site and that then authenticates the tool (codex offers this, plus other tools).

Also came across this tool that could perhaps be utilized?

Thanks!

[paulodearaujo]

Short version: not through a supported OpenAI API flow today.

OpenAI treats ChatGPT subscriptions and API billing separately. Codex is a specific exception: OpenAI officially supports signing the Codex clients into a ChatGPT plan, but that does not turn the account into a general-purpose OAuth credential for third-party OpenAI-compatible services. The distinction is documented in ChatGPT Plus billing and Using Codex with your ChatGPT plan.

Busbar also does not currently have the required interactive authorization-code/device flow or refresh-token storage. Its outbound OAuth modes are machine-to-machine grants (jwt-bearer and oauth-client-credentials), while OpenAI/Responses providers expect a bearer API key (current provider configuration).

The linked openai-oauth project takes a different route: it reuses Codex credentials and proxies the ChatGPT Codex backend. Its own README calls the project unofficial, says those credentials should be treated like passwords, and warns that the underlying service can change or disappear (legal section). So it could be tested as a local sidecar, with Busbar pointed at its OpenAI-compatible endpoint, but I would not make it a native or production Busbar authentication method.

For a reliable Busbar setup, use an OpenAI API key. If OpenAI later publishes a third-party OAuth contract for subscription-backed API access, then adding a proper interactive auth adapter to Busbar would make sense.

[MattJackson]

Apparently I am only just getting notifications for these so apologies for the later than desired response. Glad to see people using us and trying things out!!

Frank, great question and honestly one I will look into and see about how we can implement this. I would just have to tread carefully as its not an official path with OpenAI so building something that could break at any moment is risky.

Thanks @paulodearaujo! Genuinely good answer and it's correct on every point. Confirming from the Busbar side, and adding the bit that's actionable today.

What you're picturing is very close to something Busbar already does. We have a login page (as of 1.5.2, so < 48 hrs old): you open it in a browser, sign in with your identity provider, and busbar hands you a key. So "click a link, log in, you're connected" is already how busbar can work. See https://getbusbar.com/docs/token-exchange/

The difference is direction. That page signs you in over SSO and gets you a Busbar key to validate with Busbar. What you're after is the reverse: Busbar signing in to OpenAI as you, so your ChatGPT subscription pays for the calls.

As Paulo said, Codex can do it because it's OpenAI's own client and they made a deliberate exception for it. The door is there and the OAuth flow is real, but it only opens for OpenAI's own client ID. We would have to mimic Codex, since you cannot register your own app. Possible, but not 'correct' per se.

I have logged this here : #42 so we can have further discussion and Ill look into this.

If you ever want to chat reach out here (I have notifications enabled now) or email matthew@getbusbar.com or schedule some time to chat 1:1 https://calendly.com/busbar

Thank you both!
Matthew

[frankyw]

Thank you guys for the responses. I won't claim to understand all the technical intricacies but do get what you are saying @paulodearaujo about how the openai-oauth project works.

That said, there are projects that authenticate using oauth and allow user to login to their openai accounts and authenticate. Hermes, Openclaw, Opencode are such examples, and they do seem to use codex, but without me installing any codex client. Not sure exactly what is bundled. Basically it prints a token that you enter in the browser and are then authenticated.

This is a supported route by OpenAI too, it was confirmed on X, so the opposite to Anthropic.

As you can see from the screenshot, Hermes is using codex but also creating its own session separate from any installed codex cli (there is none on this machine). I was thinking busbar could maybe take the same approach.

Thanks again!

[frankyw]

Here's the link from the X post https://github.com/openai/codex/tree/main/codex-rs/app-server

[paulodearaujo]

You're right. I was too categorical about the supported integration path.

The official Codex app-server exposes ChatGPT browser and device-code login, and OpenAI's Python SDK installs the matching Codex runtime automatically. Busbar would not need a separately installed Codex CLI or the unofficial openai-oauth proxy. It could integrate with the official Codex runtime instead.

The remaining distinction is that this creates a Codex session, not a general OpenAI API credential. For Busbar, that would mean adding Codex as a separate backend rather than using the ChatGPT subscription to authenticate its existing OpenAI Responses provider.

Thanks for the correction.

App-server authentication: https://github.com/openai/codex/blob/main/codex-rs/app-server/README.md#auth-endpoints

Python SDK authentication: https://github.com/openai/codex/blob/main/sdk/python/docs/getting-started.md#2-authenticate-when-needed

[MattJackson]

Frank, your X link was right, and it mattered. We verified that post independently and it is genuine, from a verified OpenAI account, so your read was correct and it is why we kept digging on OpenAI after ruling the others out.

We went and tested this properly rather than reasoning about it: four providers, device-code flows, using our own registered application in each case. The findings are long enough that they belong with the broader question rather than buried here, so I have written them up in #42, which I opened after this thread because the answer turned out to be bigger than OpenAI.

Short version for anyone landing here: OpenAI confirms what I said above, the flow is real but the door only opens for a client id we would not own. GitHub Copilot is the most promising of the four and is still being tested. MiniMax and Kiro are both no, Kiro for an interesting reason. And a handful of providers already work today with a token you paste, which we had under-documented.

Details, evidence and the reasoning are in #42.

@paulodearaujo, your answer was correct on every point, including the parts we only confirmed by testing.