WCAG 2.1 AA & PDF/UA In-Browser Analyzer

PDF Accessibility Checker Online — Free WCAG 2.1 & PDF/UA Audit

Check PDF accessibility against WCAG 2.1, PDF/UA (ISO 14289), and Section 508 standards online for free. Audit tags, alt text, and reading order in browser.

Tag Structure DetectionLanguage /Lang CheckFigure /Alt VerificationDisplayDocTitle Audit100% In-Browser Privacy

DROP PDF FILES HERE

Upload documents to verify WCAG 2.1 and PDF/UA accessibility compliance

100% local browser processing

WCAG 2.1 & PDF/UA compliance check

Detailed JSON audit report

Quick Start

How PDF Accessibility Checker Works

Scan document catalog trees, audit compliance tags, and export detailed JSON reports in three simple steps.

Upload Document Queue

Select or drag your PDF documents into the local browser sandbox. Files are indexed strictly in client RAM with zero server transmission.

Analyze Structure & Tags

Our analyzer inspects catalog structure trees, BCP 47 language tags, figure /Alt attributes, and window display preferences.

Download Compliance Audit

View comprehensive accessibility scorecards on-screen and export complete JSON audit reports with zero server latency.

Core Capabilities

Four Core Accessibility Audits

Evaluate essential Section 508, ADA Title III, and WCAG 2.1 AA digital reading criteria directly inside your browser.

Structure Audit

Document Tag Tree (/StructTree)

Inspects catalog dictionaries to confirm the presence of /StructTreeRoot nodes, verifying whether screen readers can identify headings, tables, and logical paragraphs.

Structure compliance metric

Phonetics Validation

Language Declarations (/Lang)

Scans document catalog and metadata streams for valid IETF/BCP 47 language codes, ensuring text-to-speech synthesizers apply proper pronunciation.

Language tag validation

Visual Accessibility

Alternative Text Auditing (/Alt)

Audits all embedded figure XObjects and visual widget annotations to detect missing or empty /Alt descriptions required by WCAG 1.1.1 guidelines.

Figure alt-tag audit

Window Headers

Display Title Preference

Checks /ViewerPreferences for /DisplayDocTitle true attributes, confirming that screen readers and web browsers present descriptive titles rather than raw filenames.

Title preference status

Architecture Analysis

Utilvo In-Browser Checker vs Cloud Platforms

Compare diagnostic depth and security differences between client-side AST inspection and traditional cloud compliance checkers.

Evaluation Dimension	Utilvo Accessibility Checker	Traditional Cloud Compliance Checkers
Audit Privacy & Data Security	100% Client-Side In-Memory (Zero server uploads)	Transfers private corporate files to external servers
Inspection Depth	Direct catalog dictionary AST & byte stream analysis	Surface text scans producing false passes on untagged files
Processing Latency	Instant browser execution with zero network queue delays	Upload bottlenecks and remote queuing latency
Audit Report Export	One-click detailed JSON compliance report download	Locked behind paywalls, signups, or restricted summaries
Usage Limits & Cost	100% Free, unlimited document audits, no registration	Restricted daily credits and expensive monthly plans

Deep Dive

Automated WCAG 2.1, Matterhorn Protocol & Section 508 Tag Checks

Technical specifics on structural AST verification, BCP 47 language validation, and read-only memory sandboxing.

Catalog /StructTreeRoot Node Traversal

ISO 14289-1 mandates that all accessible content reside within a logical structure tree declared via the /StructTreeRoot entry in the document catalog dictionary. Our parser evaluates the existence of structure element hierarchies and /Marked boolean flags required for assistive tech speech engines.

BCP 47 Language Syntax Validation

Under WCAG 2.1 Success Criterion 3.1.1, the default human language of each document must be identifiable. The auditor parses /Lang strings against standardized IETF/BCP 47 language subtag registries to ensure screen readers apply correct accent pronunciation and dialect phonetics.

Figure XObject & Annotation Alt-Text

Non-text elements like charts and logos must convey equivalent information through alternative text. The engine traverses page resource dictionaries and annotation arrays to verify that non-decorative graphical objects specify non-empty /Alt strings rather than unannounced silent placeholders.

ViewerPreferences & Window Title Sync

WCAG 2.4.2 requires pages to have titles that describe their topic. The auditor verifies the presence of /DisplayDocTitle true inside the /ViewerPreferences dictionary, ensuring window title bars present descriptive document titles rather than raw filesystem paths.

Preparation

Key PDF Accessibility Errors Checked (Alt Text, Headings & Language)

Verify these key authoring factors before initiating automated digital accessibility audits.

Export With Native Tags

Confirm your authoring software (e.g. Word, InDesign) exported documents with tagged structural hierarchy enabled.

Verify Language Code

Ensure the primary document language is correctly set to an IETF BCP 47 code such as "en-US" or "fr-FR".

Review Image Descriptions

Confirm meaningful images feature informative alternative text while purely decorative graphics are tagged as artifacts.

Declare Window Title

Ensure document metadata includes a descriptive title and viewer preferences specify display title mode.

Specifications

Accessibility Audit Matrix

Technical specification standards and diagnostic criteria evaluated by the in-browser analyzer.

Audit Vector	Compliance Benchmark	Processing Engine	Output Structure	Memory Model	Recommended Use Case
Tagged Structure (/StructTreeRoot)	PDF/UA-1 § 7.1	Client-Side Parser	Boolean pass / fail & score	Direct RAM buffer	Verifies screen reader logical reading order
Language Tags (/Lang)	WCAG 2.1 Rule 3.1.1	Client-Side Parser	BCP 47 string validation	Direct RAM buffer	Ensures accurate TTS vocal phonetics and accents
Image Descriptions (/Alt)	WCAG 2.1 Rule 1.1.1	Client-Side Parser	Figure alt-text detection	Direct RAM buffer	Detects missing descriptions on visual diagrams
Display Title Preference	WCAG 2.1 Rule 2.4.2	Client-Side Parser	ViewerPreferences validation	Direct RAM buffer	Ensures descriptive titles appear in window headers

Got Questions?

Frequently Asked Questions

Everything you need to know about in-browser PDF accessibility auditing and WCAG conformance.

What compliance standards does the PDF Accessibility Checker evaluate?

It audits PDF documents against WCAG 2.1 AA and ISO 14289 (PDF/UA) standards, inspecting structure trees, natural language tags, and alternative text.

Does the accessibility checker upload my confidential files to a server?

No. The entire document inspection runs 100% client-side in your browser memory. Your confidential PDFs are never uploaded or stored on external servers.

Why is the /StructTreeRoot tag essential for screen reader accessibility?

The /StructTreeRoot dictionary establishes the logical reading sequence, ensuring screen readers announce headings, lists, and paragraphs in order.

Can this checker detect missing image alternative descriptions (/Alt)?

Yes. It inspects image and figure dictionary entries across every page, identifying visual objects that lack descriptive /Alt text for assistive tech.