Read Without an Internet Connection
Our reader detects when a device loses connectivity and automatically adjusts the interface. Core reading features remain available for content that has already been loaded; features that require a server connection are disabled until the connection is restored.
Use this reference to understand which features are available offline, how caching works per content type, and how reading analytics behave during offline sessions.
Prerequisites
- The reader must have opened the product at least once while online so the content is available in the browser or app cache.
- For audiobooks, the audio files must have been streamed and cached by the app. Audio is not available offline if the reader has never played the product.
Offline Indicator
When connectivity is lost, our reader displays a notification bar at the top of the footer. The bar is styled to match the active theme and fades in automatically. It fades out when the connection is restored. No action is required from the reader.
Features that require a server connection appear grayed out or hidden. Tapping or clicking a disabled control has no effect.
Feature Availability by Network Status
Core Reading Features
| Feature | Online | Offline | Notes |
|---|---|---|---|
| Document viewing | Yes | Yes | Content must be cached |
| Page navigation | Yes | Yes | |
| Page layout changes | Yes | Yes | |
| Theme selection | Yes | Yes | |
| Zoom controls | Yes | Yes | |
| Table of contents | Yes | Yes | |
| Thumbnails (PDF) | Yes | Yes | |
| Reading progress | Yes | Yes |
Features Requiring a Connection
| Feature | Online | Offline | Reason |
|---|---|---|---|
| Search | Yes | No | Requires server-side text search |
| Notebook | Yes | No | Syncs annotations with server |
| Highlights | Yes | No | Requires sync to save |
| Notes | Yes | No | Requires sync to save |
| Vito AI | Yes | No | AI processing runs on server |
| Listen (TTS) | Yes | No | Uses cloud text-to-speech |
| Dictionary | Yes | No | Fetches definitions from server |
| Translation | Yes | No | Uses translation API |
| Smart Zoom | Yes | No | Requires article layout data |
| Social sharing | Yes | No | Requires internet to post |
Smart Zoom is an adaptive zoom mode that reflows PDF content around a selected article zone. It requires server-side article layout data and is unavailable offline.
Feature Availability by Content Type (Offline)
| Feature | EPUB | Audiobook | |
|---|---|---|---|
| Content viewing | Yes | Yes | Yes* |
| Navigation | Yes | Yes | Yes |
| Table of contents | Yes | Yes | N/A |
| Thumbnails | Yes | N/A | N/A |
| Playlist | N/A | N/A | Yes |
| Theme | Yes | Yes | Yes |
| Zoom / font size | Yes | Yes | N/A |
| Page layout | Yes | Yes | N/A |
| Search | No | No | N/A |
| Notebook | No | No | N/A |
| Vito AI | No | No | N/A |
| Listen (TTS) | No | No | N/A |
*Audiobook playback offline requires that the audio files were previously cached by the app.
Content Caching by Format
Our reader caches content differently depending on the product format.
PDF: Pages are loaded as images. Once a page has been rendered, the browser caches it. Thumbnails use the same image sources and cache the same way. Pages the reader has never opened are not cached and cannot be viewed offline.
EPUB: Chapters are loaded through the EPUB spine. Chapters the reader has opened are cached by the browser. Navigation within cached chapters works offline. Chapters never opened are not available.
Audiobook: Audio files are cached by the Fenice app (iOS, Android, macOS, Windows) as the reader plays through the content. The playlist panel and playback controls work offline for cached audio. The web reader does not cache audio files for offline playback.
Offline Analytics
Reading activity is tracked even when the device is offline, in the Fenice mobile and desktop apps. Events such as session starts, page changes, and reading time are stored locally on the device and synced automatically when connectivity is restored.
Tenant analytics reports reflect actual reading behavior regardless of whether the reader was online or offline during the session. Timestamps preserve the real moment each event occurred, not the sync time.
| Property | Behavior |
|---|---|
| Event queue | Stored locally on the device |
| Sync trigger | Automatic on reconnect; no reader action required |
| Timestamps | Reflect the actual reading time, not the sync time |
| Analytics completeness | Offline sessions are included in tenant reports |
| Platform scope | Fenice apps (mobile and desktop) only |
The web reader requires an active connection for analytics. Reading activity during offline sessions in the browser is not captured.
Limitations
- Content that has never been loaded cannot be read offline. The reader must open each product at least once while online.
- Annotations (highlights, notes) cannot be created or saved offline. Any attempt to annotate while offline is blocked until connectivity is restored.
- Offline analytics tracking is available in Fenice apps only. The web reader does not queue analytics events during offline sessions.
- Audio files for audiobooks are not available offline on the web reader. Only Fenice apps cache audio for offline playback.
Related Documentation
- Find Text in a Product - Search availability by content type
- Play and Navigate Audiobooks - Audiobook playback and offline behavior
- Reader Feature Overview - Full feature catalog with platform availability