History Backfill: safely syncing your older ChatGPT conversations

History Backfill helps ChatEngram discover and sync your existing ChatGPT history, so your archive is not limited to conversations created after installing the extension. It is intentionally slow and conservative to protect your ChatGPT account.

0. Why History Backfill exists

  • Many users have months or years of valuable ChatGPT conversations from before they installed ChatEngram.
  • Copying those chats by hand is not realistic; History Backfill gives you a guided way to bring that history into your local archive.
  • It focuses on safety and stability: it uses ChatGPT's official APIs and throttles requests so you do not trigger rate limits or account flags.

1. What History Backfill actually does

  • It runs only on ChatGPT (chatgpt.com / chat.openai.com) when you are signed in and visit the site in a browser where the extension is installed.
  • It first asks ChatGPT for a list of conversations and saves lightweight placeholder conversations in ChatEngram: title, timestamps, and URL.
  • Message lists for those placeholders are kept empty at first; this makes the initial sync much lighter and avoids stressing ChatGPT with thousands of heavy detail requests.
  • Full content is then filled in gradually, using a slow, queued background process that calls ChatGPT's official conversation detail endpoints.

In practice, you will see conversation titles appear in the dashboard first. The actual messages for those conversations only become available after ChatEngram has safely pulled them from ChatGPT, which may take time for large histories.

2. How to run History Backfill

  1. Install and activate the ChatEngram extension in your browser.
  2. Open https://chatgpt.com or https://chat.openai.com and sign in to your ChatGPT account.
  3. After a short delay, ChatEngram detects your unsynced history and shows a green banner in the top right corner of the ChatGPT page.
  4. The banner tells you how many conversations are still unsynced and explains that backfill uses a low request rate to protect your account.
  5. Click Start sync to begin. A progress view will show how many conversations have been processed and which title is currently being synced.
  6. You can click Cancel at any time; the extension stops the current batch and you can resume later.

For very large histories, History Backfill automatically limits each run to a safe batch size. You can run backfill multiple times if you have thousands of old chats.

3. What to expect during sync

  • Backfill is deliberately slow sync — roughly about one conversation per second in order to stay within ChatGPT's normal rate limits.
  • The process runs only while the ChatGPT tab is open; closing the tab or the browser will pause it until you start backfill again.
  • All requests are made using your existing logged-in session. ChatEngram does not store your OpenAI credentials and does not attempt to bypass ChatGPT protections.
  • If ChatGPT starts showing unusual captchas, verification prompts, or errors, you should click Cancel and try again later.

4. When full conversation content appears

History Backfill is designed to prioritize safety and discoverability over immediate full content for every single item:

  • The first pass stores each ChatGPT conversation as a placeholder in ChatEngram — you will see the titles and links appear in the dashboard even before messages are available.
  • Full message content is only synced for conversations that are actually opened at least once in ChatGPT. Reopening gives ChatEngram a safe opportunity to call the official detail API and capture the full conversation.
  • This means very old chats you never revisit may remain title-only placeholders in ChatEngram, which is usually good enough for search and navigation.

If you want to be sure that certain older conversations are fully archived, simply open them once in ChatGPT after running History Backfill. ChatEngram will then sync the full content in the background.

5. Platform support and future plans

  • Today, History Backfill is available only for ChatGPT. Other platforms do not yet expose a stable, well-documented history API that can be used safely for bulk backfill.
  • ChatEngram already supports automatic capture for many platforms in real time. For older conversations on those platforms, you can still import data via their export tools and ChatEngram's import flows.
  • If additional providers eventually offer safe, well-supported history endpoints, History Backfill may be extended to them — but only where it is technically feasible and aligned with their terms of use.