Highlight PDFs in the extension
Open online PDFs in the ZetaMarker extension viewer, create highlights, add comments, and manage them from the PDF sidebar.
Highlight PDF documents in the ZetaMarker extension viewer — the same workflow as web pages, with PDF-specific navigation.
Which PDFs work in the extension
| PDF source | Extension viewer |
|---|---|
Online PDF (https://…) | Yes — opens in ZetaMarker PDF viewer |
Local file (file://) | No — use Highlight local PDF files |
| Google Drive / Google Docs | No — upload to dashboard instead |
Open a PDF and highlight
- Navigate to an online PDF URL in your browser.
- ZetaMarker opens the PDF in its extension viewer (toolbar + sidebar).
- Select text on a single page (multi-page selections are not supported).
- Pick a color from the floating toolbar — same five colors as web highlighting.
- The highlight saves locally; if signed in, it syncs to the cloud.
Toolbar and sidebar
After highlighting, use the toolbar to:
- Change color
- Add or edit a comment
- Copy highlighted text
- Delete the highlight
Open the sidebar to list all highlights on the PDF, sort them, and jump to each passage. Sort options: Earliest, Latest, By position.
Cloud sync for PDFs
When signed in with cloud sync active:
- Highlights sync to your dashboard
- Use Refresh highlights from cloud in the PDF menu after edits elsewhere
- Sync conflicts show Refresh highlights or Reload page — see Sync conflicts
Legacy PDF highlights may need migration first.
Limits
- Select text on one page at a time — spanning multiple pages in one selection is not supported.
- Very large PDFs (150+ pages) may show longer migration times when upgrading legacy highlights.
Related
- Highlight local PDF files
- View PDFs in the dashboard
- Fix highlights after PDF migration
- Edit a highlight — same color and comment controls on web and PDF