About Aura Books
A free, offline audiobook player that respects your privacy and the files you already own.
The problem we built around
Most audiobook software falls into one of two camps. On one side are the big streaming services — Audible, Spotify, Libby — which work beautifully but lock the books inside their app, tie them to a subscription or library card, and broadcast every page-turn back to their servers. On the other side are desktop players like SmartAudiobookPlayer, BookFusion, or VLC, which give you full ownership but are stuck on one device and rarely work as well on a phone as they do on a laptop.
Aura Books sits in the gap. It plays the files you already have — M4B chapters and all, MP3 folders, M4A files ripped from your own discs — but it does it in the browser, so it works on every device without an install. And it does it without a server, so your listening history never leaves the device.
What “offline-first” actually means here
When you import a file, Aura Books stores the audio blob in your browser’s IndexedDB. That is the same database mechanism every modern browser uses for offline data — Gmail uses it to let you draft messages without a signal, Spotify uses it for the web player’s offline cache. Once a book is imported it lives entirely on your device. You can put the phone in airplane mode, walk into a tunnel, board a flight — playback never depends on a network connection.
The first time you open the site we register a service worker. That worker caches the app shell so subsequent visits load instantly, even when offline. The audio files themselves are not served through the worker — they come straight from IndexedDB via blob URLs, which lets the browser stream them efficiently and skip seamlessly between chapters.
What we don’t collect
- No account. There is no sign-up, no email, no password.
- No analytics on your listening habits. We do not know what you listen to, how long, or how often.
- No upload. Your files never touch our infrastructure.
- No telemetry. The app does not phone home with error reports or usage data.
The only network requests Aura Books makes are: (1) loading the app itself from the server, (2) fetching Google Fonts (Geist, Instrument Serif) the first time you visit, and (3) on public-facing pages like this one, we may show a small Google ad to help cover hosting costs. The player at /app stays ad-free.
How the technology fits together
Aura Books is built with Angular 21 as a Progressive Web App. The key components are:
- IndexedDB for persistent storage of audio blobs, book metadata, cover images, and listening sessions. We use three object stores so a corrupt write to one doesn’t damage the others.
- A single HTMLAudioElement that lives for the life of the tab. This is the same element the browser uses for the lock-screen now-playing controls and the Bluetooth headset buttons, which means your hardware skip buttons work out of the box.
- A Web Worker for waveform generation and color-palette extraction so the playback thread stays responsive even when scrubbing through a 20-hour book.
- music-metadata-browser plus a custom binary atom reader for M4B chapter extraction. Most players miss the chapter atoms inside M4B files — ours reads both Nero (
chpl) and QuickTime (trak/tref/chap) encodings, so the chapters are right whether your file came from Audiobook Builder, mp4chaps, or Plex. - Service worker with a cache-first strategy for hashed assets and a network-first strategy for the app shell, so you always run the latest build when online and never lose access offline.
The roadmap, briefly
We’re a small project and we ship slowly on purpose. Things on the near-term list:
- OPDS catalog support so you can pull books from your own home library server.
- Better chapter editing for files where the embedded metadata is wrong or missing.
- Optional, end-to-end encrypted cross-device sync — only if it can be done without us ever seeing your library.
- A “recently listened to” export so you can keep reading stats even if you wipe site data.
If something is missing that would make Aura Books the right player for you, open the app and send the suggestion via the Settings → Feedback link.
The team and the funding
Aura Books is built by one person in their evenings. There is no company, no funding round, no exit plan. The cost to keep it online is small and is covered by ads on these public marketing pages — the player itself is and will remain ad-free. If you find the app useful and want to support its development you can share it with a friend, which costs you nothing and is the most useful thing you can do.
Ready to try it? Open the player →