Book-to-audiobook API
Book-to-audiobook API converts EPUB, PDF, or TXT files into chaptered M4B audiobooks.
What Book-to-audiobook API is
Book-to-audiobook API converts EPUB, PDF, or TXT files into chaptered M4B audiobooks. Narration is offered in 602 languages, with three quality tiers and a voice choice before generation. The service also offers narration in the user’s own cloned voice. Finished files can be downloaded with chapter markers. Uploads accept files up to 50 MB, with EPUB recommended because PDF and TXT results vary. Jobs run asynchronously and can be followed through a status URL or an optional callback webhook. Sats4AI documents L402 over HTTP, MCP, and WebLN for developer integrations. Payment is per use in Bitcoin Lightning sats, with no account or card required. The pay-per-audiobook plan is billed from 500 sats, priced per character, and shows a quote before generation. Uploaded files remain for 72 hours to handle conversion faults, then are deleted. Sats4AI says it does not create customer accounts or sell usage data, while retaining operational records needed to deliver and protect the service.
Good
- Converts EPUB, PDF, and TXT files
- Offers narration in 602 languages
- Provides three quality tiers and voice cloning
- Exports chapter-marked M4B files
- Supports asynchronous API jobs and webhooks
Watch out
- No free plan or free trial
- Uploads are limited to 50 MB
- PDF and TXT results may vary
- Payment requires Bitcoin Lightning sats
Who it suits
It suits readers, publishers, and developers who need chaptered audiobooks from common document formats. It is also relevant for multilingual narration, cloned-voice projects, and API-based workflows.
Verdict
Book-to-audiobook API combines broad language coverage, chaptered M4B output, and developer integration options. Its pay-per-use model and file limits should be considered before production use.
Plans and prices
From Book-to-audiobook API's own pricing page, checked 7 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Pay per audiobook | — | EPUB, PDF, or TXT · up to 50 MB · three quality tiers · from 500 sats · priced per character · quote shown before generation |
The facts
Each one read from Book-to-audiobook API's own pages, with the date it was checked.
What it does
- API job handling
- Audiobook jobs run asynchronously and can be checked through a status URL or an optional callback webhook.checked 7 Oct 2026
- Book conversion
- The service turns EPUB, PDF, or TXT files into chaptered M4B audiobooks.checked 7 Oct 2026
- Chapter markers
- Completed audiobooks are downloadable as M4B files with chapter markers.checked 7 Oct 2026
- Developer integrations
- Sats4AI documents L402 over HTTP, MCP, and WebLN as integration options for its services.checked 7 Oct 2026
- File handling
- Uploaded files are kept for 72 hours to address conversion faults, then deleted.checked 7 Oct 2026
- Input limits
- The upload form accepts EPUB, PDF, or TXT files up to 50 MB and recommends EPUB because PDF and TXT results vary.checked 7 Oct 2026
- Language coverage
- The product page says audiobooks can be narrated in 602 languages.checked 7 Oct 2026
- Payment and access
- The service charges per use in Bitcoin Lightning sats and requires no account or card.checked 7 Oct 2026
- Privacy
- Sats4AI says it does not create customer accounts or sell usage data, and describes keeping operational records needed to deliver and protect the service.checked 7 Oct 2026
- Support
- The company says it can be reached through its contact page and Nostr.checked 7 Oct 2026
- Voice cloning
- The product page offers audiobook narration in the user's own cloned voice.checked 7 Oct 2026
- Voice options
- Users choose among three quality tiers and select a voice before generation.checked 7 Oct 2026
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