Using your ChatGPT plan for AI requests in other apps: OpenAI's "Sign in with ChatGPT"
Published
This English page is a machine translation of the Korean original, so some phrasing may read awkwardly.
A new sign-in feature lets other apps handle AI requests using the user's ChatGPT Plus or Pro allowance, with users setting weekly limits for each app.
Read the original at OpenAI Help Center ↗
The biggest concern when adding AI features to a small app is the cost of model calls, which grows with usage. OpenAI has opened a way to cover that cost through the user's ChatGPT subscription.
OpenAI included "Sign in with ChatGPT" in its DevDay 2026 recap published on September 29. Signing in to a participating app with a ChatGPT account lets the app handle AI requests using the ChatGPT Work and Codex allowance included in your plan.
Anyone can sign in, but only Plus and Pro users can use their plan's allowance. At the time of the announcement, 16 companies were participating, including Devin, Notion, and Vercel.
The app receives your name, email address, and profile photo. It does not receive your API keys, conversation history, or memories.
I see this as a fairly big change for app developers. They have less to worry about when setting free usage limits or deciding whether to ask users for API keys.
But a closer look at how the limits work shows it is not that simple.
Users set a weekly usage limit for each app in settings. This is not a reserved allocation, but a cap on the percentage of the total allowance that the app can use. So an app can stop working even when some of the total allowance remains. That allowance is also shared with other apps connected to the same account.
There is another problem after users hit a limit. To keep using the app with their remaining credits, users must manually enable credit usage and set that app's limit to 100%. Credit usage is off by default, and the app does not automatically switch to another paid option.
So if the allowance runs out in the middle of a task, explaining the situation to the user falls to the app.
It needs to tell users whether they have hit the app's limit or the overall limit, and show them how to continue their work. The cost shifts to the user's subscription, but explaining the situation remains the app's responsibility.
Sources
- OpenAI: DevDay 2026 Recap, September 29, 2026.
- OpenAI Help Center: Using your ChatGPT plan in other apps and sites, accessed September 30, 2026.
A question to think about
If our service's AI features run on the user's ChatGPT plan, what should we show when their allowance runs out?