Install the extension
Signing in with ChatGPT needs a small browser extension. This is a limitation of the OAuth flow itself, not a shortcut we took.
Why an extension is required
OpenAI's OAuth client only accepts one redirect address: http://localhost:1455/auth/callback. A website on the public internet can never receive that callback, so something running in your browser has to catch it and hand the result back to us — which is exactly what this extension does, and all it does.
It requests no access to your browsing. Its only permission is declarativeNetRequestWithHostAccess scoped to localhost:1455, so it can redirect that one address and read nothing else — no cookies, no history, no other sites.
Download for Chromium
Download and unzip
Chrome installs a folder, not a zip file, so extract it somewhere you will not delete it — moving or removing this folder disables the extension.
Open chrome://extensions
Paste that URL into a new tab. It is a built-in page, so it will not open from a link here.
Turn on Developer mode
The toggle sits in the top-right corner of that page.
Load unpacked
Pick the folder you unzipped — the one with manifest.json directly inside it — and the extension appears in the list.
Come back and connect
Return to the dashboard and press Connect ChatGPT. The page detects the extension and continues on its own.
Loaded this way, Chrome nags about disabled developer-mode extensions on every launch and the extension is not auto-updated. That is the price of installing before a store listing exists — the button above will point at the Chrome Web Store instead once it is live, and nothing else about your setup changes when it does.
Download for Firefox
Download and unzip
Anywhere you can find again — Firefox reads the folder you select.
Open about:debugging
Go to the This Firefox section. Like chrome://extensions, this is a built-in page.
Load Temporary Add-on
Choose manifest.json inside the unzipped folder.
Come back and connect
Return to the dashboard and press Connect ChatGPT.
Firefox treats an add-on loaded this way as temporary and removes it when the browser restarts, so you will repeat these steps after a restart until the store listing is live.
Then you are done
This is the only setup step on your side. Everything after it — the token handoff, the API keys, the endpoint — happens on the dashboard.