[adamzwasserman]

This is exactly right. Client-side processing for sensitive data like contacts eliminates the trust problem entirely. Most migration tools want you to upload your entire contact database to some random server when the extraction can happen locally in milliseconds.

Pure client-side tools like this should be an option for any personal data processing.

This is what I have done for my users: an option to import their emails to an in-browser db for guaranteed privacy.