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Horn

github.com

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Spec score 7.7 #103 of 169 in Accessibility Testing Software

Spec sheet

Purpose
Horn is an open-source PDF/UA accessibility checker based on the Matterhorn Protocol.Read 12 Oct 2026 · github.com
Free plan
YesRead 23 Sep 2026 · github.com
License
The project site says Horn is released under the MIT and Apache 2.0 licenses.Read 12 Oct 2026 · horn.report
Automated scans
YesRead 23 Sep 2026 · github.com
Browser extension
NoRead 23 Sep 2026 · github.com
CI/CD integration
YesRead 23 Sep 2026 · github.com
CI/CD output
Horn supports SARIF for GitHub Code Scanning, JUnit XML, and JSON output.Read 11 Oct 2026 · horn.report
Customization
The site says developers can add custom checks with the Check trait.Read 11 Oct 2026 · horn.report
Desktop platforms
The README describes Linux, macOS, and Windows support, and the releases page lists binaries and desktop installers for those platforms.Read 12 Oct 2026 · github.com
Extensibility
The README says custom checks can be added through the Check trait.Read 12 Oct 2026 · github.com
GitHub Action
The site says the GitHub Action supports automatic SARIF upload.Read 11 Oct 2026 · horn.report
GitHub integration
The GitHub Action can automatically upload SARIF results to GitHub Code Scanning.Read 12 Oct 2026 · github.com
GitLab integration
The README includes a GitLab CI example that publishes JUnit XML as a test report artifact.Read 12 Oct 2026 · github.com
Manual review limit
The site identifies 48 human-judgment conditions for manual review and 2 conditions without a defined test.Read 11 Oct 2026 · horn.report
Manual review tools
YesRead 23 Sep 2026 · github.com
Matterhorn checks
For Matterhorn Protocol 1.1, Horn automates 87 machine-checkable conditions and surfaces 48 human-judgment conditions for manual review.Read 12 Oct 2026 · github.com
Mobile testing
NoRead 23 Sep 2026 · github.com
Output formats
Horn supports human-readable text, JSON, SARIF, and JUnit XML output.Read 12 Oct 2026 · github.com
PDF standards
Horn validates PDF/UA-1 and PDF/UA-2 documents.Read 12 Oct 2026 · github.com
PDF/UA coverage
The site says Horn automates 87 machine-checkable Matterhorn Protocol 1.1 conditions and surfaces 48 human-judgment conditions for manual review.Read 11 Oct 2026 · horn.report
Performance
The project README reports approximately 660 PDFs per second with parallel processing in release mode.Read 12 Oct 2026 · github.com
Release
The GitHub releases page lists v0.4.0 as the latest release.Read 12 Oct 2026 · github.com
Runtime dependencies
The site lists 0 runtime dependencies.Read 11 Oct 2026 · horn.report
Speed
The site says Horn processes 500+ PDFs per second with parallel processing.Read 11 Oct 2026 · horn.report
Usage limit
The README identifies 48 human-judgment Matterhorn conditions as manual-review items rather than automated checks.Read 12 Oct 2026 · github.com
Validation corpus
The site says Horn scores 100% on the veraPDF PDF/UA-1 corpus.Read 11 Oct 2026 · horn.report
Ways to use
The site lists a CLI, desktop app, WebAssembly browser version, npm package, GitHub Action, and Docker.Read 11 Oct 2026 · horn.report
Ways to use it
The project site lists a CLI, desktop app, browser WebAssembly build, npm package, GitHub Action, and Docker as ways to use Horn.Read 12 Oct 2026 · horn.report
WCAG coverage
other standardRead 23 Sep 2026 · github.com

Where Specifiction places it

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