Ace by DAISY review
A focused, free EPUB checker with reports, remediation guidance, and developer integrations.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Ace by DAISY is a free, open-source accessibility checker for EPUB files. It is designed for publishers, self-publishing authors, production teams, and service providers that need automated checks during an EPUB publishing workflow. The tool evaluates EPUB accessibility requirements and selected WCAG-related rules, then presents findings across violations, metadata, document outlines, and images. Its EPUB specialization makes it a focused choice for digital book production rather than a general accessibility platform.
Ace supports several ways to fit testing into a production process. Teams can use its command-line interface, desktop graphical application, HTTP API, or JavaScript/Node module integration. It also integrates with axe and supports filtering and sorting of reported violations. HTML and JSON exports make results practical for review or downstream workflow use, while accessibility metadata editing and EPUB re-saving extend the product beyond scan output. These options suit both editorial users and technical teams working with automated publishing or CI/CD processes.
The strongest reason to choose Ace is its depth within EPUB accessibility: reports include multiple inspection views, and detected issues come with remediation details and suggestions. However, its scope is intentionally narrow. It is not intended for native mobile applications or broad web accessibility testing, and automated checks cover only part of an accessibility evaluation. Manual inspection remains necessary. Choose Ace when EPUB is the primary format and a free, open-source tool with command-line and API options fits the workflow. Choose an alternative when testing must span websites, mobile apps, or broader manual evaluation needs.
Ace by DAISY pros and cons
- Where it wins
- Free, open-source automated testing for EPUB content documents
- HTML and JSON reports cover violations, metadata, outlines, and images
- CLI, desktop, HTTP API, and Node integration support publishing workflows
- Where it doesn't
- Focused on EPUB publications rather than general web accessibility testing
- Automated checks cover only part of accessibility evaluation
- Does not provide native mobile application testing
Ace by DAISY fact sheet, pricing and score →
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