Vincent Rozenberg
60da5a53e8
A Chrome MV3 extension that exports a full ChatGPT history to JSON in the shape of ChatGPT's own conversations.json, for the Amgreat Gemini migration tool. Everything runs in the user's browser against their own session. Batches of 25 per file, downloaded through the service worker because Chrome blocks multiple page-initiated downloads. Adaptive pacing with 429 backoff, Retry-After support, token refresh and localStorage resume.
ChatGPT export extension (Amgreat)
A small Chrome extension that exports a user's full ChatGPT history to JSON
files — no paywall, no limits, nothing leaves the browser. Its output has the
same shape as ChatGPT's official conversations.json, so it drops straight into
the migration tool.
Current version: 1.4, shown in the footer of the extension's own window, so you can tell which build a machine actually has loaded.
How it works
Runs as a content script on chatgpt.com, in the page's own origin, so it uses
the user's existing logged-in session. It calls ChatGPT's own internal API
(/backend-api/conversations to list, /backend-api/conversation/{id} to fetch
each in full), assembles them into a JSON array, and offers it as a download.
That is exactly what the paid extensions do — the paywall is artificial.
A green "Export for Gemini" button appears bottom-right on ChatGPT. Click it
and a window opens showing each step and a progress bar. Conversations download
in batches of 25, one file per batch, named
chatgpt-export-<date>-partN.json. Feed all of them to the migration tool at
once.
Two details worth knowing:
- Downloads go through the service worker. Chrome blocks a page from
starting more than one download, so
background.jsperforms them viachrome.downloads. The blob URL has to be created in the content script, because service workers have noURL.createObjectURL. - The pace adapts. It starts at 1.5s between conversations, speeds up while
requests succeed, and backs off 1.3x on every HTTP 429, honouring
Retry-Afterwhen ChatGPT sends one. After sustained throttling it takes a five-minute rest rather than hammering. Progress is saved tolocalStorage, so an interrupted run resumes at the right batch instead of starting over.
Free accounts throttle hard at roughly 33 conversations. Paid accounts run at about 21 conversations a minute.
Try it yourself (unpacked, 1 minute)
- Chrome →
chrome://extensions→ toggle Developer mode (top right) on. - Load unpacked → pick this folder.
- Open/refresh chatgpt.com → the green button is bottom-right → click it.
- Leave the window open. Files land in Downloads as each batch completes.
Rolling it out to 30 people
Don't ask non-savvy staff to enable developer mode. Two clean options, both using tools you already have:
- Force-install via Google Admin Console (recommended). You manage Chrome through Workspace already. Zip this folder, host it (or publish it unlisted to the Chrome Web Store), then Admin Console → Devices → Chrome → Apps & extensions → add it as Force install for the org. It appears for everyone automatically, no clicks, no developer mode.
- Unlisted Chrome Web Store item. Publish once (one-time $5 dev fee), share the private link; users click "Add to Chrome". Simpler than self-hosting, and it auto-updates.
Either way the extension stays yours and free of limits.
Notes / limits
- Text only. Conversations come across in full; image/file attachments do not (same as the migration tool).
- The user must be logged in to ChatGPT in that browser; the window says so if they are not. The session token refreshes automatically if it expires part-way through a long run.
- A large history takes a while. It fetches one chat at a time on purpose, to stay under ChatGPT's rate limits; half an hour is normal for a few hundred conversations.
- If ChatGPT changes its internal API, the two endpoint paths in
content.jsmay need updating. They are the only ChatGPT-specific parts.