Join our free live webinar and master PDF validation with veraPDF – the industry-supported open-source validator
Validate PDFs the right way. Join the experts behind PDFix to explore veraPDF — the only open-source PDF/UA and PDF/A validator trusted and supported by the digital preservation community. Learn how to install veraPDF, choose the right validation profiles, run batch accessibility checks, interpret validation results, and correct accessibility issues using PDFix.
Key Takeaways
VeraPDF is the only open-source validator recognized by the industry and maintained under the Open Preservation Foundation and aligned with the PDF Association’s PDF/A Technical Working Group.
This webinar will show you exactly why veraPDF matters, and how to use it correctly.
- Why PDFix Chose to Integrate veraPDF Into Our Products
- What is veraPDF and How Does It Validate
- How to Install and Use veraPDF
- FREE PDFix Desktop Lite
- PDFix Desktop / SDK Integration: Validate and Fix in One Workflow
Webinar Source: Validate PDF/UA with veraPDF – Complete Guide
Frequently Asked Questions
What is veraPDF?
veraPDF is an open-source PDF validator covering all parts of the PDF/A and PDF/UA (Matterhorn Protocol Machine failure conditions) standards. Originally funded by the PREFORMA project, veraPDF has been sustained and maintained by the Open Preservation Foundation since 2017. Dual Lab provides active user support and carries out maintenance and bug fixes. The PDF Association’s PDF/A Technical Working Group continues its role in resolving ambiguities arising from veraPDF’s usage in the field.
Is veraPDF suitable for accessibility teams?
Yes. It is industry supported open-source standard with active maintenance and PDF community governance. It validates PDF/UA requirements, highlights common tagging and structure errors, and produces validation reports you can trust. See the full list of PDF/UA validation profiles.
Where do I get the PDF validation reports?
veraPDF outputs HTML, XML, or JSON with detailed findings, errors, and fail summaries.
Where can I try the veraPDF validator online?
Use the veraPDF Web Demonstrator or the PDFix online validator (pdfix.io) to run PDF/UA checks directly in your browse.
Is veraPDF a free PDF accessibility checker?
Yes. veraPDFis free and open-source – you can download it, use it, and modify it to meet your needs.
What if there is an error in veraPDF validation?
If you encounter a validation result that appears incorrect, we encourage you to report it on the veraPDF GitHub issue tracker or reach out to the Open Preservation Foundation. Community feedback is essential to improving veraPDF. You can also volunteer your time and expertise by contributing to the software and documentation via GitHub (https://github.com/veraPDF)
Why choose PDFix Desktop Lite over the official free veraPDF desktop application?
veraPDF desktop is a great validator, but PDFix Desktop Lite makes the results practical to work with.
- PDFix Desktop Lite:
- Integrates the same veraPDF validation engine directly into a PDF viewer/editor.
- Shows validation results in a dedicated panel.
- Groups issues by type (e.g., natural language, images, structure).
- Lets you click an issue and jump directly to the problematic object on the page or in the structure tree.
- Supports batch validation across many files, with a combined view of issues.
So if you not only want to check conformance but also understand and work with the problematic content, Desktop Lite offers a much more usable wo
Does PDFix use the identical veraPDF validation engine without modifications or additions?
Yes. This means the validation results in PDFix match what you would get from the official veraPDF distribution (for the same profile and version). PDFix uses the latest official veraPDF engine. When PDFix needs improvements or bug fixes, they contribute changes upstream to the veraPDF open-source project.
In our typesetting software, figures/tables/formulas appear inside <P> in the accessibility tags. Can PDFix move them out of the paragraph tag and make them siblings?
Yes, this kind of structural fix is possible in PDFix.
- PDFix provides a “Delete Tags” action that:
- Deletes selected tag types (e.g.,
<P>) based on rules. - Lets you decide what happens to nested content:
- Leave content in place,
- Move nested tags up to the parent level, or
- Mark the content as artifact.
- Deletes selected tag types (e.g.,
- You can define a custom template that targets only the structures you want.
Example from the webinar:- Delete
<P>tags whose parent is<TR>, and move nested tags up one level.
- Delete
Applied to your case, you can:
- Target
<P>tags that contain figures/tables/formulas. - Use the “move nested tags to parent” option.
- This effectively lifts the figure/table/formula out of the paragraph and places it as a sibling tag.
If needed, PDFix support can help define the exact template logic for your layout.
veraPDF doesn’t validate contrast issues in the default profile. Do you have any recommendation for contrast detection, or is PAC still the best tool?
Key points:
- veraPDF:
- The default PDF/UA profile does not include color contrast checks.
- A more complete / WCAG-oriented profile does contain a color contrast test.
- The contrast algorithm and thresholds in veraPDF may differ from other tools.
- You can inspect and even adjust the color contrast check in the profile XML if you have specific criteria.
- PAC and other tools:
- PAC is still widely used for color contrast validation.
- Different tools may report different results because they use different algorithms or interpretation rules.
Recommended approach:
- For critical workflows, review or customize the veraPDF contrast check to match your internal requirements.
- Use multiple validators (e.g., PAC + veraPDF with a profile that includes color contrast checks).
Can we get detailed error reports (HTML, JSON) directly from PDFix Desktop Lite?
Yes, you can generate veraPDF validation reports directly from PDFix Desktop Lite. The UI lets you:
- Run validation with a chosen profile.
- Generate a veraPDF report as: HTML, XML
- Open the report inside PDFix and then save it (e.g., as HTML or convert to PDF for sharing).
JSON:
- CLI / Docker / SDK integration → HTML / XML / JSON, depending on how you call veraPDF.
- veraPDF itself can output JSON via its command-line usage.
- JSON is typically accessed in automation/SDK or Docker-based workflows, rather than through the basic Lite UI.
So: Desktop Lite UI → HTML / XML reports
What is the maximum volume of documents PDFix SDK handles efficiently per batch?
There is no fixed hard limit in the SDK itself. Throughput and “efficient volume” depend on:
- Your hardware (CPU cores, RAM, disk/IO).
- Parallelization strategy (how many processes/threads you run).
- Complexity and size of the PDFs.
- What actions you perform (validation only vs. validation + fixing + conversions).
Real capacity is determined by how you architect your batch/queue system, not by a built-in limit in SDK. PDFix SDK can be used:
In continuous workflows, processing thousands to millions of documents.
In parallel processes (e.g., multiple CLI or worker instances).
After validation, how can I test PDFs with a screen reader on macOS, since NVDA isn’t available and VoiceOver is not commonly used?
NVDA is Windows-only, so it’s not an option on Mac. The main native screen reader on macOS is VoiceOver:
- Use VoiceOver together with Adobe Acrobat Reader DC or Acrobat Pro for realistic PDF testing.
- Built-in viewers (like Preview) generally don’t expose full tag/structure information the way screen readers need.
Alternative / complementary method:
- Use PDFix conversion to HTML as a proxy for reading order:
- PDFix can convert tagged PDFs to HTML using the document structure (tag tree) as the reading order.
- You can then review:
- Heading levels (H1, H2…),
- Reading order,
- Grouping of content.
- This is not a replacement for an actual screen reader, but it’s a very useful additional check based on the same tag structure that assistive tech relies on.
- Recommended practice: Optionally, combine this with PDF → HTML conversion via PDFix to visually inspect reading order and tag structure.
- On Mac: Use VoiceOver + Acrobat Reader/Pro for hands-on accessibility testing.
