What happens to my highlights if read library ebooks such as Libby?
If you read your Libby books on a Kindle device or in the Kindle app, the highlights will be automatically synchronized with Readwise. Here are the instructions on how to Read with Kindle while using the Libby app.
All notes and highlights are preserved in your Kindle account after a library book loan ends. You can find your library book highlights that you've read with your Kindle device or in the Kindle app here: https://read.amazon.com/notebook. (It's also best practice to make sure you're highlights and notes are uploaded to Amazon prior to your library loan expiring.)
If you read and highlight in the Libby app itself, Libby recently added exporting of highlights to a comma separated value (CSV) file. You can download this file and rearrange its columns to to upload to Readwise via the CSV Import option. If there's enough demand, we may create a special parser for Libby. (Let us know if this is something you would use.)