Mia Perese
Published April 15, 2026
Updated May 05, 2026
3 min
New Side-by-Side Interaction Capabilities in Multiviewer
What's new in WebViewer 11.12: Multiviewer
Mia Perese
Multiviewer has always been built for working across multiple documents at once. WebViewer 11.12 extends this with support for annotations, markup, and document manipulation in both panes. Developers can now build workflows where documents aren't just viewed side by side; they can be marked up and manipulated simultaneously, without leaving the Multiviewer layout.
What's new in WebViewer 11.12: Multiviewer
Expanded Multiviewer capabilities
Multiviewer was originally optimized for reference and comparison use cases. It enabled users to view multiple documents at once, making it easy to review similarities and differences across files. With this release, Multiviewer now supports all the interaction capabilities available in WebViewer across all supported file types.
Before this release, users could:
- Open multiple documents side by side or in a multi-tab view
- Compare PDFs, Office files, images, and other WebViewer file types
- Scroll, zoom, and review content synchronized or independently
These capabilities were ideal for viewing multiple documents, but users had more advanced use cases when comparing files. Common multi-document comparison scenarios include:
- Contract redlining: make corrections to one version of a document while keeping the original visible for side-by-side review
- Patient intake: modifying a PDF while referencing an uploaded image or supporting file
- Engineering review: displaying two versions of a technical document to verify measurements, apply markups, or validate changes
Supported file combinations
Multiviewer supports two panes. Each pane can load any file type supported by WebViewer, including PDFs, images, and Office files for viewing. Both panes can load different file types simultaneously, as long as each file is in a supported format. For example, a PDF and an image can be viewed and compared at the same time.
Scrolling behavior
Pane scrolling is configurable. Developers can set panes to scroll independently or in sync, depending on what the workflow requires.
What stays the same
The existing Multiviewer capabilities are all still in place:
- Open multiple documents in a side-by-side or multi-tab layout
- Compare PDFs, Office files, and images
- Scroll, zoom, and navigate synchronized or independently
- Configurable UI, consistent with standard WebViewer
Document comparison in Multiviewer
Multiviewer offers base document comparison support. For more advanced requirements, two WebViewer add-ons are available:
- Semantic comparison: identifies meaningful content differences rather than visual ones, making it useful for comparing document versions where formatting may have changed alongside content.
- Image overlay comparison: renders two document pages on top of each other, so reviewers can visually inspect differences between versions.
For full details, see the comparison capabilities page.
Licensing
Multiviewer is included with base WebViewer. Advanced comparison features (semantic comparison and image overlay) are available as add-ons.
Also new in WebViewer 11.12
With the latest enhancements to Multiviewer, users can review, validate, and act in one place. This update aligns with enhancements across the Web SDK’s other editors. DOCX Editor now supports comments for review workflows that don’t require direct content changes, while Spreadsheet Editor offers in-app chart interaction for adjusting data and visuals.
These improvements streamline tasks where users shift between documents, spreadsheets, and comparison views. Explore the full set of updates in the Web SDK release notes or start testing WebViewer’s Multiviewer capabilities in the Showcase.
Frequently asked questions
Multiviewer now supports the ability to:
- scale and measure across both documents.
- Crop across both documents.
- Insert and delete pages across both documents.
- Search across both documents.
- See the right number of pages in the page navigation across both documents.
Two panes. Each pane loads its own document and operates as an independent WebViewer instance.
Yes, with some constraints. Any two WebViewer-supported file types can be loaded simultaneously; for example, a PDF and an image.
Scrolling behavior is configurable. Developers can set panes to scroll independently or in sync, depending on the workflow.
