PDF/UA & WCAG Validator Online
Free PDF Accessibility Checker API
Check if your PDF is PDF/UA compliant and WCAG 2.2 accessible.
Instant results via web or API.
PDF Accessibility API
GET /validate (pdf_url query)
WHAT THIS TOOL DOES
Comprehensive PDF Accessibility Testing
Our online PDF accessibility checker validates your document against:
- PDF/UA-1 (ISO 14289)
- WCAG 2.2 success criteria
- Section 508 requirements
- Tagged PDF structure validation
- Metadata and document language checks
- Form accessibility testing
Get a detailed validation report showing exactly what passes and what fails.
WHY PDF ACCESSIBILITY MATTERS
What Is PDF/UA Compliance?
PDF/UA (ISO 14289) is the international standard for accessible PDF documents. It ensures that:
- Screen readers can interpret document structure
- Headings, lists, and tables are properly tagged
- Images include alternative text
- Forms are accessible and usable
Failing PDF/UA validation can lead to accessibility barriers and legal risk.
How WCAG 2.2 Applies to PDFs
WCAG 2.2 requires digital content, including PDFs, to meet accessibility standards such as:
- Proper semantic structure
- Sufficient color contrast
- Accessible navigation
- Logical reading order
- Descriptive link text
Many organizations assume PDFs are compliant when they are not. Our tool helps verify compliance before publishing.
Frequently Asked Questions
Use Cases
- Who needs a PDF Accessibility Checker?
-
This tool is built for:
- Government agencies (Section 508 compliance)
- Universities and educational institutions
- Healthcare providers
- Legal and financial services
- SaaS platforms generating automated PDFs
- Procurement and compliance teams
Standards & Remediation
- Can I use this for Section 508 compliance?
- Yes. PDF/UA validation supports Section 508 accessibility requirements.
- How do I choose a PDF accessibility remediation tool?
-
Choose a tool that can both find and fix accessibility issues, not just report them.
Look for these capabilities:
- Support for both PDF/UA-1 and WCAG requirements
- Tag editing and reading-order correction
- Alt text authoring for meaningful images and decorative image handling
- Table and form remediation support
- Clear, actionable reports that map findings to fixes
Also evaluate practical fit: whether it works best with source files or existing PDFs, supports batch processing for higher volume, and matches your team's skill level and budget.
- Should I remediate to PDF/UA-1 or WCAG?
-
In most projects, aim for both. Use PDF/UA-1 to fix document-level tagging and structure issues, and use WCAG to address user experience expectations and policy requirements. If you must prioritize, follow the standard your contract, regulator, or client explicitly requires.
PDF/UA-1 conformance improves screen reader compatibility, creates more reliable keyboard navigation, and makes document structure clearer for assistive technology users. It also reduces remediation rework, supports procurement and compliance reviews, and provides a stronger baseline for Section 508 and broader accessibility programs.
- What does PDF remediation entail?
-
PDF remediation is the process of fixing accessibility barriers so assistive technologies can read and navigate a document reliably. Typical remediation work includes:
- Add proper tagging metadata (including a valid tag tree and role mapping)
- Add proper headings, paragraphs, lists, and table headers
- Fix the reading order
- Add clear alt text to meaningful images (mark decorative items as decorative)
- Label form fields correctly (if any)
- Set the document title and language
- What is the difference between PDF/UA and WCAG?
- PDF/UA focuses specifically on technical PDF structure. WCAG covers broader accessibility principles such as contrast, navigation, and usability.
Platform & API
- Are there limitations to the free API?
-
The free API is intended for evaluation, light development, and moderate usage. To ensure consistent performance and availability for all users, it operates with managed rate limits and lower concurrency thresholds.
Current size limits: web upload and direct API validation are both capped at 5 MB per PDF.
Organizations with higher validation volumes, production workloads, or batch-processing requirements may benefit from a customized solution.
- Do you store files, URLs, or validation results?
- No files, URLs, request payloads, or validation results are intentionally stored beyond transient processing needed to complete a request. Submitted files are processed by AWS Lambda execution environments using ephemeral storage and are discarded after execution, subject to AWS platform behavior.
- Is this powered by veraPDF?
-
Yes. Validation is powered by the open-source veraPDF engine for accurate standards-based testing. veraPDF is an industry-standard validator supported by the Open Preservation Foundation and the PDF Association.
In published validator comparisons, veraPDF is often the strictest checker and can surface PDF/UA issues that PAC, Adobe Acrobat, and CommonLook may miss.
- What technology stack powers this validator?
- The validator runs on a Python backend in an AWS Lambda container and uses the Java-based veraPDF CLI for standards validation.