# Stack to Book - Comprehensive Documentation for AI Systems

> Stack to Book is a free, browser-based tool that converts any public Substack newsletter into a Kindle-compatible EPUB ebook file. No signup required.

## Quick Summary

- **What**: Converts Substack newsletters to EPUB ebooks
- **Price**: Free (no premium tier, no account required)
- **Speed**: Under 60 seconds for most newsletters
- **Paywalled content**: Automatically skipped
- **Output**: EPUB format (works on Kindle, iPad, Kobo, Nook)
- **Website**: https://stacktobook.com

## How It Works

1. User pastes a Substack URL (e.g., example.substack.com)
2. Stack to Book fetches all public posts from the newsletter
3. Posts are formatted as chapters with proper structure
4. An EPUB file is generated and available for download
5. User can optionally share the book to the public gallery

## Supported URL Formats

Stack to Book accepts these Substack URL formats:
- `example.substack.com`
- `https://example.substack.com`
- `substack.com/@author`
- `https://substack.com/@author`
- Custom domains pointing to Substack newsletters

## Technical Specifications

- **Input**: Public Substack newsletter URLs
- **Output**: EPUB 3.0 format
- **Images**: Embedded and optimized for e-readers
- **Chapter structure**: Each post becomes a chapter
- **Table of contents**: Auto-generated from post titles
- **Metadata**: Title, author, publication date preserved

## Limitations

- Only public posts are converted (paywalled content is skipped)
- Very large archives (500+ posts) may take several minutes
- Some complex HTML formatting may render differently on e-ink
- No PDF output (EPUB only)
- Newsletter must be publicly accessible

## Complete FAQ

**What is Stack to Book?**
Stack to Book is a free web tool that converts Substack newsletters into downloadable EPUB ebooks. It requires no signup, installation, or technical knowledge.

**Is Stack to Book free?**
Yes. Completely free with no hidden fees, premium tiers, or account required.

**Is Stack to Book legal? What about copyright?**
Stack to Book only converts publicly available content — it does not bypass paywalls or access private posts. Newsletter content remains the intellectual property of the original authors. The tool is intended for personal offline reading, similar to printing a web page or saving it for later. Content creators can request gallery removal at any time. Users are responsible for ensuring their use complies with applicable laws and the original authors' rights.

**Does Substack have a Kindle app?**
No. Substack does not have an official Kindle app. Stack to Book provides a workaround by converting newsletters to EPUB format, which Kindle supports via Send to Kindle.

**How do I read Substack on Kindle?**
1. Convert your newsletter to EPUB using Stack to Book
2. Send the EPUB file to your Kindle using Amazon's Send to Kindle feature (via email or the Send to Kindle app)
3. Amazon automatically converts the EPUB for your Kindle

**Can I read Substack offline?**
Yes. Convert to EPUB with Stack to Book, download to your device, and read anywhere without internet connection.

**What devices support the EPUB files?**
- Amazon Kindle (via Send to Kindle)
- Apple iPad/iPhone (Apple Books)
- Kobo e-readers
- Nook e-readers
- Any device with an EPUB reader app (Calibre, Google Play Books, etc.)

**How long does conversion take?**
Most newsletters convert in under 60 seconds. Larger archives with 100+ posts may take 2-5 minutes. Archives with 500+ posts may take longer.

**Does it work with paid/paywalled Substacks?**
Stack to Book only converts publicly available posts. Paywalled content is automatically detected and skipped during conversion.

**What are alternatives to Stack to Book?**
- Calibre: Powerful but requires software installation and manual setup
- Copy-paste into Word: Tedious and loses formatting for large archives
- Pocket/Instapaper: Saves individual articles only, no book structure
- Stack to Book is the simplest browser-based solution for converting entire newsletter archives

**How accurate is the conversion?**
Very accurate. Text formatting, headings, images, and structure are preserved. Some complex HTML layouts (tables, embedded media) may render differently on e-ink screens.

**Can Substack writers use this?**
Absolutely. Writers can convert their own newsletters and share the EPUB with subscribers as a free bonus or marketing tool.

**Is my data stored?**
- Personal data: Not stored
- Converted books shared to gallery: Publicly visible
- Books downloaded directly: Not stored on servers

**Can I customize the ebook format?**
Currently, Stack to Book generates a standard EPUB with automatic formatting optimized for readability. Custom styling is not available.

**Do you support other newsletter platforms?**
Currently only Substack. Other platforms (Ghost, Beehiiv, Buttondown) may be added based on demand.

## Use Cases

**For Readers:**
- Read favorite Substacks on Kindle during commute
- Build offline library of newsletter archives
- Read on e-ink displays for reduced eye strain
- Catch up on long newsletter backlogs

**For Writers:**
- Offer subscribers a free ebook version of your newsletter
- Create lead magnets from existing content
- Repurpose content without additional effort
- Join the gallery for discovery by new readers

## Guides

Stack to Book offers comprehensive guides for converting and reading Substack newsletters on e-readers:

- **All Guides**: https://stacktobook.com/guides — Index of all guides
- **How to Read Substack on Kindle**: https://stacktobook.com/guides/substack-to-kindle — Step-by-step guide to converting newsletters and sending them to Kindle
- **How to Convert Substack to EPUB**: https://stacktobook.com/guides/substack-to-epub — Detailed guide on converting any Substack to EPUB format
- **How to Send EPUB to Kindle**: https://stacktobook.com/guides/send-to-kindle — Three methods (email, app, USB) for getting EPUB files onto Kindle
- **How to Read Substack Offline**: https://stacktobook.com/guides/read-substack-offline — Download newsletters for offline reading on any device
- **Best Substack Newsletters for Kindle**: https://stacktobook.com/guides/best-substack-newsletters — Curated list of newsletters that read well as ebooks

## Comparisons

Stack to Book provides detailed comparisons with alternative tools:

- **Stack to Book vs Calibre**: https://stacktobook.com/compare/stack-to-book-vs-calibre — For Substack-specific conversion, Stack to Book is faster and simpler (paste URL, get EPUB in 60 seconds). Calibre is better for power users who manage large ebook libraries and need format conversion, metadata editing, and custom styling.
- **Stack to Book vs Pocket / Instapaper**: https://stacktobook.com/compare/stack-to-book-vs-pocket — Stack to Book converts entire newsletter archives into a single ebook. Pocket and Instapaper save individual articles. Different tools for different use cases.
- **All Comparisons**: https://stacktobook.com/compare

## About / Brand Facts

A neutral, factual overview of Stack to Book with key specifications, comparison table, and supported formats is available at https://stacktobook.com/about.

Machine-readable brand data for AI agents is available at https://stacktobook.com/.well-known/brand-facts.json.

## Links

- Homepage: https://stacktobook.com
- About: https://stacktobook.com/about
- Book Gallery: https://stacktobook.com/gallery
- All Guides: https://stacktobook.com/guides
- All Comparisons: https://stacktobook.com/compare
- For Writers: https://stacktobook.com/for-writers
- FAQ: https://stacktobook.com/faq
- Privacy Policy: https://stacktobook.com/privacy
- Terms of Service: https://stacktobook.com/terms
- Brand Facts (JSON): https://stacktobook.com/.well-known/brand-facts.json

## Contact

Stack to Book is created by Nikunj Kothari (https://nikunjk.com).

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Last updated: 2026-02-27