Terms of Service for Éist

Last updated: September 15, 2026

Acceptance of Terms

By downloading, installing, or using Éist (“the app”), you agree to these Terms of Service. If you do not agree, please do not use the app.

Description of Service

Éist is an audiobook reader application that:

Converts ebook files (EPUB, PDF) to audiobooks using AI text-to-speech
Operates primarily offline on your device
Does not require account registration
Collects anonymous usage analytics and crash reports to improve stability

Analytics & Crash Reporting

Éist uses PostHog for anonymous usage analytics and Sentry for crash reporting. These services collect:

Device type, OS version, and app version
Anonymous events: app opens, playback actions, book imports, and subscription events
Crash stack traces and performance metrics

Your books and personal data are never sent. You can opt out completely in Settings → Privacy, which disables both analytics and crash reporting.

User Responsibilities

Permitted Use

You may use Éist to:

Import and convert ebooks you legally own or have rights to access
Download and use free public-domain books from integrated sources
Listen to audiobooks for personal, non-commercial purposes

Prohibited Use

You may NOT use Éist to:

Convert or distribute copyrighted content without authorization
Circumvent digital rights management (DRM)
Use the app for any illegal purpose

Content Ownership

Your books: You retain all rights to content you import.
AI voice models: Third-party voice models remain subject to their respective licences and the additional terms below.
Public-domain content: Free books from Project Gutenberg are in the public domain.

Supertonic Model Terms

Éist distributes the Supertonic 3 model weights and voice styles, © 2026 Supertone Inc., under the BigScience Open RAIL-M License. The accompanying Supertonic runtime code is MIT licensed. Supertone does not endorse Éist.

By downloading or using Supertonic voices through Éist, you agree to paragraph 5 and Attachment A of the Open RAIL-M License, which are incorporated into these terms. You may use the model only lawfully and must not use it or its derivatives:

in violation of applicable law or regulation;
to exploit, harm, or attempt to exploit or harm minors;
to generate or disseminate verifiably false information or content for the purpose of harming others;
to generate or disseminate personally identifiable information that can be used to harm an individual;
to generate or disseminate content without expressly and intelligibly disclosing that it is machine generated;
to defame, disparage, or harass others;
to impersonate or attempt to impersonate others, including through deepfakes, without their consent;
for fully automated decision-making that adversely affects legal rights or creates or modifies a binding obligation;
to discriminate against or harm people based on social behaviour or known or predicted personal or personality characteristics;
to exploit vulnerabilities associated with age or social, physical, or mental characteristics in a way likely to cause physical or psychological harm;
to discriminate based on legally protected characteristics or categories;
to provide medical advice or interpret medical results; or
for administration of justice, law enforcement, immigration, or asylum decisions or profiling, including predictions that a person will commit fraud or crime.

If you share audio created with a Supertonic voice, you must clearly identify it as machine generated. The complete licence controls if this summary differs from it. A copy is available in the app under Settings → About → Open source licences, on our Supertonic licence page, and alongside the model download.

Intellectual Property

Éist, including its design, code, and AI voice technology, is protected by intellectual property laws. You may not:

Copy, modify, or distribute the app
Reverse engineer the app or voice models
Use our trademarks without permission

Disclaimer of Warranties

THE APP IS PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND. WE DO NOT GUARANTEE:

Uninterrupted or error-free operation
Accuracy of text-to-speech synthesis
Compatibility with all devices or file formats

Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, WE SHALL NOT BE LIABLE FOR:

Any indirect, incidental, or consequential damages
Loss of data or content
Interruption of service

Changes to Terms

We may modify these terms at any time. Continued use of the app after changes constitutes acceptance of the new terms.

Termination

We reserve the right to terminate your access to the app if you violate these terms.

Governing Law

These terms are governed by the laws of Ireland, without regard to conflict-of-law principles.

Contact

For questions about these terms, contact us at [email protected].

Thank you for using Éist. Enjoy your audiobooks!