Stack to Book and Pocket / Instapaper solve different problems. Pocket and Instapaper save individual articles for later reading — great for a handful of posts. Stack to Book converts an entire Substack newsletter archive into a single EPUB ebook with chapters and a table of contents — ideal for reading a full backlog on Kindle or any e-reader. If you want to save 3 articles for the weekend, use Pocket. If you want to turn 200 newsletter posts into a book you can read offline, use Stack to Book.
Side-by-Side Comparison
| Feature | Stack to Book | Instapaper | |
|---|---|---|---|
| What it saves | Entire newsletter archive | Individual articles | Individual articles |
| Output format | EPUB ebook | In-app only | In-app / EPUB (premium) |
| Table of contents | Auto-generated | No | No |
| Chapter structure | Each post = chapter | Separate articles | Separate articles |
| Kindle support | EPUB via Send to Kindle | Send to Kindle (one by one) | Send to Kindle (one by one) |
| Offline reading | Yes (EPUB file) | Yes (app required) | Yes (app required) |
| Requires account | No | Yes | Yes |
| Requires app | No (browser-based) | Yes | Yes |
| Price | Free | Free / $4.99/mo premium | Free / $5.99/mo premium |
| Best for | Complete newsletter archives | Individual article saving | Individual article saving |
The Core Difference
Pocket and Instapaper are read-it-later apps. You browse the web, find an article, save it to read when you have time. They're excellent at this — clean reading views, offline access, cross-device sync.
Stack to Book is an archive-to-ebook converter. It takes an entire Substack newsletter — every public post — and turns it into a single, properly structured ebook. Chapters, table of contents, embedded images, the works.
These are fundamentally different tools for different use cases:
- Save one article from today's newsletter — use Pocket or Instapaper
- Read the entire archive of a newsletter — use Stack to Book
- Read a newsletter on Kindle as a proper ebook — use Stack to Book
- Build a reading queue from multiple sources — use Pocket or Instapaper
Why Not Just Save Every Post to Pocket?
You could save 100 Substack posts to Pocket one by one. But you'd have:
- 100 separate items in your reading queue (no book structure)
- No table of contents or chapter navigation
- No single file you can send to Kindle
- A reading queue that becomes overwhelming and unmanageable
With Stack to Book, those 100 posts become one cohesive ebook. Open it on your Kindle, tap the table of contents, jump to any chapter. It reads like a book because it IS a book.
Kindle Reading: Stack to Book vs Pocket
Pocket offers a "Send to Kindle" feature, but it sends individual articles. For a newsletter with a large archive, you'd need to send dozens or hundreds of articles separately — each appearing as a separate document on your Kindle.
Stack to Book generates a single EPUB. Send it to your Kindle once. It appears as one book in your library with proper chapter navigation. The reading experience is dramatically better for long newsletter archives.
Use Them Together
The best workflow for avid newsletter readers:
- Pocket / Instapaper for your daily reading queue — saving individual articles from RSS feeds, newsletters, and web browsing
- Stack to Book for when you discover a new Substack and want to read through the archive — convert the full backlog into an ebook for your Kindle
Frequently Asked Questions
Can Pocket save an entire Substack newsletter?
No. Pocket saves individual articles one at a time. Stack to Book converts the full archive into a single EPUB ebook.
Can I read Pocket articles on Kindle?
Pocket has a Send to Kindle feature but sends individual articles, not complete archives. Stack to Book produces a proper EPUB ebook with chapter navigation.
Is Stack to Book better than Instapaper for Substack?
For full archives, yes. Instapaper saves individual articles. Stack to Book converts entire newsletters into ebooks. For saving a few posts, Instapaper works great. For reading backlogs, Stack to Book is purpose-built.