Nutrient DWS Accessibility API vs veraPDF

Nutrient DWS Accessibility API processes PDFs to add accessibility tags and check conformance. It returns a tagged PDF with PDF/UA metadata and targets PDF/UA-1 (ISO 14289-1). Tagging covers H1–H6 headings, ordered and unordered lists, table rows and cells, reading order, annotations and decorative artifacts. The API accepts HTTP requests from any programming language, with quickstarts for Java, C#, JavaScript, Python and PHP. Nutrient reports 96.5% PDF/UA conformance across a validation corpus of 3,157 files. Its free plan costs nothing and includes 20 auto-tagged pages and 100 validations per month. Starter costs $79 a month for 200 pages and 1,000 validations; Professional is $249 a month for 1,000 pages and 5,000 validations; Business is $499 a month for 3,000 pages and 15,000 validations. Monthly quotas do not roll over, and requests in a quota category are blocked when that quota runs out unless a larger plan or pay-as-you-go is used. Auto-tagging does not guarantee full accessibility compliance, so Nutrient recommends QA, especially for sensitive or high-stakes documents.

veraPDF is an open source validator for PDF/A and PDF/UA conformance. Its Implementation Checker validates all PDF/A parts and conformance levels, and performs machine checks for PDF/UA parts 1 and 2. The Policy Checker evaluates PDF Features Reports against institutional policy profiles. A Metadata Fixer makes a limited set of repairs, such as removing an incorrect PDF/A flag or repairing broken XMP when that is the only obstacle to a legitimate flag. The Reporter transforms machine-readable reports from the Implementation Checker, Policy Checker, and Metadata Fixer into other forms for downstream use. Developers can use the validation library as a Java archive through Maven, a desktop GUI, or a command-line application. Plugins can add third-party feature extraction tools to PDF Features Reports. The project describes digital preservationists and memory institutions as key users, and offers an API and test files for developers. Desktop installers are available for Windows, Mac, and Linux; these systems need Java 8 or later. veraPDF is dual licensed under GPLv3 or later and MPLv2 or later. Downloads include GPG signatures and instructions to check installer integrity. Development builds may contain bugs or missing features and come without support or guarantees. The validator costs nothing.