Book-to-audiobook API

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. Users can also request narration in their own cloned voice. Finished M4B files include chapter markers. Uploads can be up to 50 MB; EPUB is recommended because PDF and TXT results vary. Jobs run asynchronously and can be checked through a status URL or optional callback webhook. Payment is per use in Bitcoin Lightning sats, with quotes shown before generation and no account or card required. The pay-per-audiobook option starts from 500 sats and is priced per character. Files remain for 72 hours to handle conversion faults, then are deleted. Sats4AI documents L402 over HTTP, MCP, and WebLN integrations. There is no free plan or free trial.

Who it suits

It suits developers and readers who need API or web conversion of text files into narrated, chaptered audiobooks. It is also suited to users wanting many language or cloned-voice options.

Limits

The pay-per-audiobook plan bills from 500 sats and charges by character, with a quote shown before generation. Uploads cannot exceed 50 MB, and uploaded files are deleted after 72 hours.

Getting started

1. Open the Sats4AI audiobook webpage or use its API
2. Prepare an EPUB, PDF, or TXT file up to 50 MB
3. Choose a voice and one of the three quality tiers
4. Select narration in a supported language or your cloned voice
5. Review the generated quote priced per character
6. Pay per use in Bitcoin Lightning sats
7. Track the asynchronous job by status URL or callback webhook

Verdict

This service provides file-to-audiobook conversion with broad language coverage, voice choices, and developer integration options. Its pay-per-use model avoids accounts and cards but requires Lightning-sat payments.