Keep the export. Then keep something you can read.

Request the official export from Settings → Data controls → Export data. It arrives by email as a ZIP, usually within a few hours.

Download it and put it somewhere permanent. This file is your evidence: it is exactly what OpenAI handed over on that date, unmodified by any tool. It keeps working after the download link expires, after the plan changes, and after the account is closed. It is also, on its own, almost unreadable — which is why there is a part two.

The ZIP is the backup you keep. The archive is the backup you use.

Convert the export into Markdown notes, an Obsidian vault, a self-contained HTML file, or PDFs — whichever you will actually open. This is the copy you search when you want that thing you worked out in March, and the format matters far less than the fact that it opens without a specific application being alive.

Keep both. They cost almost nothing to store and they fail in different ways.

A backup you have not verified is a hope. Three things separate an archive you can rely on from one that merely exists:

• The numbers add up. Messages found, messages rendered, messages skipped — and the first equals the sum of the other two. Without that arithmetic you have no way of knowing whether a converter dropped a tenth of your history.
• Anything missing is named. Assets referenced but absent from the export are normal. What is not normal is a tool passing over them silently. Every gap should have a row somewhere with a reason attached.
• It opens without the tool that made it. Markdown and HTML open in anything. A proprietary format, a hosted workspace, or a database only your converter understands is not a backup — it is a second dependency.

Most backup routes ask you to upload your entire chat history to a service you had not heard of yesterday. That is a strange thing to do with the file you are creating specifically because you are worried about other people holding your conversations.

The converter below runs in this browser tab. The export is opened and read on your machine, and nothing is sent anywhere — which you can verify by disconnecting from the internet before you add the file. The conversion still completes, because everything it needs is already on your computer.

For most people, a couple of times a year and before anything that changes the account — a cancellation, a plan switch, a workspace migration.

Re-running the conversion over an archive you have already edited will not clobber your work: a note that has changed since it was generated is left alone, and the newly generated version arrives beside it as a separate file so you can decide what to do with it.