Fully Automated AI Service

A Professional Index. One Click.

IndexAI generates a complete, professional back-of-book index for your book — editable AI-generated index entries, added right to your manuscript.

$49 per book

200,000 words included · entries you can edit like any other manuscript text

Everything You Get

A Complete Back-of-Book IndexDIY: 10–40 hours

IndexAI reads your whole book and builds the index automatically. You could add index entries yourself in Markua — we make DIY indexing as easy as possible, but marking up a whole book by hand still takes 10–40 hours of your time.

Editable Entries, Right in Your Manuscript

IndexAI adds standard Markua index entries to your manuscript. They're yours: review them, edit them, delete them — just like any other text you wrote.

Fully Automated, Starts Immediately

No calls, no waiting for a quote. IndexAI starts the moment you buy, and we email you when your index is ready — typically within a day.

100% Money-Back Guarantee

If you're not happy with your index, we'll refund your purchase. There is no reason not to try it.

DIY on Leanpub: 10–40 hours

IndexAI:
$49 USD per book

Index Your Book

IndexAI — per book

$49 USD

Who is the IndexAI Service For?

This service is for authors who want an index automatically created for their book by one of the most advanced AI models in the world.
IndexAI will create an index for your book using a leading large language model.
If you want to see unmodified examples of indexes created by IndexAI, Leanpub's founder Peter Armstrong ran IndexAI on two of his Leanpub books, Lean Publishing and Aphantasia, and published the result 100% unmodified. (Both books can be purchased for $0 from those links. You can also just download them as PDFs without bothering to do the free purchases by using these short URLs: Lean Publishing (PDF) and Aphantasia (PDF).)
IndexAI requires that your book is published, 100% complete, and written in Markua 0.31.
If your book is in Leanpub Flavoured Markdown (LFM) or Markua 0.10, there are two ways for you to use IndexAI:

You can easily convert your book to Markua 0.31. We have a guide for how to convert Leanpub Flavoured Markdown (LFM) books to Markua 0.31 here, and a guide for how to convert Markua 0.10 books to Markua 0.31 here.
We can convert your book to Markua 0.31 for you as part of the Global Author service. Global Author is probably the best deal on Leanpub! It includes converting to Markua 0.31, creating an index with IndexAI, translating it into 31 languages with the TranslateAI service, creating a course with the CourseAI service, Publish on Amazon (with Max), and more! Learn more about Global Author...

What is the IndexAI Process?

The following are the exact steps we will take when you purchase the IndexAI service:

Leanpub will create a clone of your book in Source Editor mode to create the index in (so your original book is unchanged until you review the index). This book will be in "stealth mode" so that it's for your eyes only.
Leanpub will create the index in the book clone using a leading large language model
Leanpub will automatically preview your book clone with the index, and ensure that the book generates correctly. (This is automated, but in the rare case that there is a problem, we will review it manually.)
After the preview completes, Leanpub will automatically email you to review the index in the book clone.

This entire process is fully automated, and typically takes under 4 hours. Leanpub staff will only review your index if there is a problem, such as if the index being empty or if the book clone fails to generate. (We have priced the IndexAI service to be very affordable, based on the assumption that no human review will be required except in rare cases of errors on our part.)
But what's next?
Once you have approved the index (making any changes you wish), the easiest way to update your original book is to do these two things:

If your original book is in Dropbox or GitHub mode, you can click a button to convert your original book to be in Source Editor mode, at Settings > Writing Mode. Of course, if your book is already in Source Editor mode, you don't need to do this step!
Go to Settings > Replace Manuscript and click a button to replace your original book manuscript with that of the book clone containing the index. We create a manuscript version before and afterward, so you can always revert to the original version if you want to.

Of course, if your original book is in Dropbox or GitHub mode, you can also just update it yourself instead of switching to Source Editor mode. What you do in this case is download the book clone manuscript which contains the index from its manuscript versions page, unzip it, and replace the contents of your original book manuscript folder with those of the clone. (However, since this process is a tiny bit of a chore, so we recommend just clicking the button! After all, since you're making an index, you're presumably done your book. So, there's no real reason not to just have us do everything for you with two clicks.)
Finally, note that IndexAI is also included in our premium Global Author concierge service. So, if you're interested in a full suite of services, including converting to Markua 0.31, creating an index with IndexAI, publishing on Amazon with the Publish on Amazon service (with Global Author Max), translating it into 31 languages with the TranslateAI service, creating a course with the CourseAI service, and promotional bonuses, check out Global Author...

IndexAI is Only $49

IndexAI is just $49. We want the price of IndexAI to be both simple and affordable.
(If you choose a book which is over 200,000 words, there is an extra charge which will be shown below. However, almost all Leanpub books are shorter than that, so chances are this doesn't apply to you.)

How Long Does It Take?

The IndexAI service is fully automated, and typically takes under 4 hours.
Due to the nature of the service, we can't guarantee a specific turnaround time. However, if you don't get an automated email within one business day, please email hello@leanpub.com and we'll look into it for you.

Leading AI Models for Great Quality Indexes

The IndexAI service uses a leading large language model for great quality AI indexing. We use one of the most advanced AI models in the world, which is perfect for creating indexes for books, and we update our choice as better models become available.

Frequently Asked Questions

Why Did Leanpub Build This?

We built IndexAI for one obvious reason: even though Markua makes it easy to add index entries, creating an index for your book is still a huge pain in the ass.
Leanpub exists to serve our authors. Writing a book is hard enough, and when you're done, the last thing most authors want to do is spend another 5 or 10 hours creating an index. Using IndexAI will save you time. That time is better spent promoting your book, or just celebrating its completion!

How Does IndexAI Work With AI?

When we index a book we split it into multiple chunks and then index those chunks. We then do a second pass to combine relevant index entries, etc. Not only are most book manuscripts much too large to fit in the working memory or "context window" of the AI, but there are also quality benefits from keeping the length of a chunk to a manageable size. So, we split the book into appropriately-sized chunks, index those chunks, and recombine the chunks into an indexed book manuscript. Then we do a second pass to combine relevant entries. This all happens automatically. Watching this process occur as the IndexAI jobs run is truly amazing: we really do live in the future!

What Dialects of Markdown Are Supported?

IndexAI works with books written in Markua 0.31. As discussed above, if your book is in Leanpub Flavoured Markdown (LFM) or Markua 0.10, you can convert it yourself to Markua 0.31, or you can use the GlobalAuthor service to do it for you.

100% Money Back Guarantee

If you're not happy with the results, or if your book is not a good fit for the service, we'll fully refund your money.
Yes, our 60 Day 100% Happiness Guarantee applies here, just like it does with all Leanpub purchases!
Now, this is technically risky for us, since you'll have the indexed manuscript either way. But we're so confident in our services and in our authors that we're happy to offer our full money back guarantee for all our services.
You can only find out how good the service is by trying it, and because of our 100% money back guarantee there's literally no risk to do so!
So, there's no reason not to try the service, is there?

The Leanpub 60 Day 100% Happiness Guarantee

Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.

See full terms...

Earn $8 on a $10 Purchase, and $16 on a $20 Purchase

We pay 80% royalties on purchases of $7.99 or more, and 80% royalties minus a 50 cent flat fee on purchases between $0.99 and $7.98. You earn $8 on a $10 sale, and $16 on a $20 sale. So, if we sell 5000 non-refunded copies of your book for $20, you'll earn $80,000.

(Yes, some authors have already earned much more than that on Leanpub.)

In fact, authors have earned over $15 million writing, publishing and selling on Leanpub.

Learn more about writing on Leanpub

Write and Publish on Leanpub

You can use Leanpub to easily write, publish and sell in-progress and completed ebooks and online courses!

Leanpub is a powerful platform for serious authors, combining a simple, elegant writing and publishing workflow with a store focused on selling in-progress ebooks.

Leanpub is a magical typewriter for authors: just write in plain text, and to publish your ebook, just click a button. (Or, if you are producing your ebook your own way, you can even upload your own PDF and/or EPUB files and then publish with one click!) It really is that easy.

Learn more about writing on Leanpub