Look at ContactPicker API for integration with Solid Contacts

[timbl]

See

https://developers.google.com/web/updates/2019/08/contact-picker#security-considerations

"Access to the user’s contacts has been a feature of native apps since (almost) the dawn of time. It’s one of the most common feature requests I hear from web developers, and is often the key reason they build a native app.

The Contact Picker API is a new, on-demand picker that allows users to select entries from their contact list and share limited details of the selected entries with a website. ..."

Look at

• Using this API in Chrome to allow a user to import their existing contacts into Solid
• Implementing the same API in Solid to allow future developers to access user's solid contacts

Note that the contact picker API is, deliberately it seems, not rich in the data. It drops things like home/work/.mobile distinctions for phone numbers. So VCARD import and DTP (and other APIS) may be the best way of importing whole contact databases.