Grackle PDF vs veraPDF

Grackle PDF has no write-up on Specifiction yet; its figures are above.

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.