E

email-migration

OpenMail Identity is an open infrastructure for portable email addresses that gives individuals and organizations lasting control over their email identity while allowing them to change providers without changing their address. It separates the address from the mailbox and delivery provider, reducing provider lock-in and making email addresses durable, portable digital identities. https://roxanneardary.com/openmail-identity/

Cross-platform desktop app that exports email from Thunderbird and Apple Mail to EML, Outlook MSG, or PST. Works entirely offline — no credentials or internet required. Built with .NET 8 and Avalonia UI.

PSTmortem is a Python CLI that exports Microsoft Outlook OST/PST files to Thunderbird mbox or Dovecot Maildir. Designed for very large archives (tested 30 GB+) with low, constant memory. Features folder & date filtering, attachment size limits, resumable Maildir exports, and graceful Ctrl-C.