Live Demo ​

Validate PDF files against PDF/UA-1 or PDF/UA-2 directly in your browser — the standard is detected from each file's pdfuaid:part. Horn runs as WebAssembly — your files never leave your device.

Every check of the Matterhorn Protocol 1.1 runs: the 87 machine-checkable conditions are reported as pass or fail with their official Matterhorn index, and the 48 conditions that need human judgment are listed per file for manual review. PDF/UA-2 files additionally get the ISO 14289-2 rules with interim ua2: ids. The demo always loads the latest released engine from npm, so it matches the current CLI and desktop release; the version in use is shown below the file picker.

This browser demo runs via WebAssembly, which is single-threaded and noticeably slower than the native CLI. For production use and accurate performance numbers, use horn validate on the command line — it processes ~660 PDFs/second with parallel execution.