A free, open-source PDF reader and annotator built for marking up scientific papers — highlights, notes, and exportable annotations.
Our take
Not a text editor — it’s an annotation-first reader, and the honest comparison is to Preview with better note-taking, not to a full PDF editor like Acrobat. Free and open source with no company behind it; worth including because it’s the free, no-catch option in a section full of subscriptions.
- Price
- Free
- License
- Open source
- Get it via
- Homebrew · Direct
- Developer
- Skim (open-source community project)
Do you use Skim?
Who made this
Are you Skim (open-source community project)? Claim this profile to add a photo, a bio, and links — or ask us to remove it.
What it does
Notes and highlights
Add and edit notes, plus one-swipe highlighting for marking up text.
Export annotations as text
Pull your notes and highlights out as plain text for reuse elsewhere.
Built for papers
Designed around reading and annotating academic PDFs, though it works for any PDF.
The deal
- Free and open source
Worth knowing: Skim is a reader and annotator, not a full text/form editor — it doesn’t rewrite PDF text or fill complex forms the way a paid editor does.
Skim — questions people ask
Is Skim free?
Yes, free and open source.
Does Skim edit PDF text?
No — it’s an annotation tool (notes, highlights) rather than a text/form editor.
Is Skim free?
Yes — Skim is free.
Does Skim work alongside a notch app like Alcove?
Yes — Skim lives in the screen, so it runs happily alongside any Dynamic Island hub or notch app.
Where can I download Skim?
Skim is available via Homebrew, Direct.
Is Skim open source?
Yes — Skim is open source.
Reviews
No public ratings yet. Reader reviews are coming to Kitsmith soon.
Listing hand-verified August 20, 2026 from the developer's site and public sources.
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