Any CSV file you upload, and any data generated by the built-in test data tools, is parsed and processed entirely in your browser's memory using JavaScript. Your raw CSV rows are never uploaded to a server, transmitted over the network, or written to any external storage.
If you're signed in, we save a private summary of each migration you run to your account so you can revisit it later. This summary includes field mapping decisions, issue types and counts, duplicate-group counts, and transformation rules — it does not include your source data values, the example snippets shown in the issues table, or the contents of duplicate records. This history is private to your account and only accessible by you.
If you're not signed in, nothing is saved: when you close or refresh the page, all data is discarded.
Files you choose to download (such as generated sample data or CRM templates) are saved locally to your own device using your browser's standard file download mechanism, and are never seen by us.