@mdgate/epub

Convert EPUB books to Markdown in TypeScript.

@mdgate/epub reads .epub and .ibooks files directly in JavaScript and converts chapters into GitHub-Flavored Markdown, without Python, native addons, WASM, or an ebook app.

Works in Node.js, Cloudflare Workers, Edge runtimes, and browsers.

npm install @mdgate/epub

import { toMarkdown } from '@mdgate/epub';

const markdown = await toMarkdown(bytes);

bytes is a Uint8Array, so the book can come from a file upload, object storage, an HTTP request, a browser file picker, or anywhere else your application gets bytes.

Why @mdgate/epub

EPUB is a ZIP of HTML plus a spine. Dumping the archive is not a book an agent can read.

@mdgate/epub is an EPUB reader written for the same runtime as your application:

• Pure TypeScript
• EPUB → Markdown locally
• No Python runtime
• No native addons
• No WASM runtime
• Zero third-party runtime dependencies
• Works with raw Uint8Array input
• Detects EPUB packages from their contents, not only the filename

What it extracts

@mdgate/epub opens the package, follows the spine, and converts chapter HTML through the shared HTML document model.

The converter handles EPUB-specific concerns including:

• spine order
• chapter HTML as Markdown
• headings, paragraphs, lists, links, and tables from the chapter markup
• iBooks packages that use the same ZIP + HTML shape

The output is Markdown that can be searched, indexed, chunked, cached, or passed directly to an AI agent.

Node.js

import { readFile } from 'node:fs/promises';
import { toMarkdown } from '@mdgate/epub';

const bytes = new Uint8Array(await readFile('book.epub'));
const markdown = await toMarkdown(bytes);

console.log(markdown);

Browser

import { toMarkdown } from '@mdgate/epub';

const file = input.files![0];
const bytes = new Uint8Array(await file.arrayBuffer());

const markdown = await toMarkdown(bytes);

Cloudflare Workers and Edge runtimes

import { toMarkdown } from '@mdgate/epub';

export default {
  async fetch(request: Request) {
    const bytes = new Uint8Array(await request.arrayBuffer());
    const markdown = await toMarkdown(bytes);

    return new Response(markdown, {
      headers: {
        'content-type': 'text/markdown; charset=utf-8',
      },
    });
  },
};

Format detection

You do not need to trust the file extension.

@mdgate/epub recognizes EPUB ZIP packages from their mimetype and container metadata.

const markdown = await toMarkdown(bytes);

A path can still be supplied as a format hint when @mdgate/epub is used through @mdgate/converters or a reader composed with @mdgate/core, but the path is never used to read a file from disk.

Compose it with other file readers

@mdgate/epub implements the converter interface from @mdgate/core.

import { create } from '@mdgate/core';
import { epub } from '@mdgate/epub';
import { pdf } from '@mdgate/pdf';

const read = create([
  epub(),
  pdf(),
]);

The application still uses one reading interface while each format remains independently installable.

Need more than EPUB?

If your application needs to read many different file types, use the complete converter set:

npm install @mdgate/converters

import { toMarkdown } from '@mdgate/converters';

const markdown = await toMarkdown(bytes, {
  path: filename,
});

@mdgate/epub is one of the single-format packages in the open-source mdgate/converters project.

For AI agents, the same converter architecture can be used to extend read_file from text files to real-world document formats.

License

MIT