Compare software

Highlights vs Skim: catalog facts
Highlights	Skim
Freemium Free to use, with advanced features in a Pro subscription that has a free trial.	Free Free and open source under the BSD licence.
macOS, iOS	macOS
Exports annotations to Markdown and popular notes apps DOI lookup and citation metadata for papers	SyncTeX integration makes it the standard viewer for LaTeX work Annotation and snapshot tools designed for reading academic papers
Apple platforms only Advanced features require a subscription	macOS only Notes are stored in Skim's own format unless explicitly embedded
Downloadable app	Downloadable app
Closed source	Open source
License not stated	License: BSD-3-Clause
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked September 22, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.