Welcome to BookKraft AI: Your Ebook Publishing Toolkit
Welcome to BookKraft AI. If you found your way here, you're probably dealing with some version of the same problem: formatting an ebook is harder than it should be.
You finished writing a book. That's the hard part. Then you discovered that getting it into a format that actually works on Kindle, Apple Books, Kobo, and every other platform is a whole other project — one that requires knowing about EPUB structure, OPF manifests, CSS compatibility, NCX files, and a dozen other technical things that have nothing to do with writing.
BookKraft AI is a suite of tools designed to handle that technical layer so you can focus on publishing.
What BookKraft AI Does
We built sixteen tools that cover the most common ebook formatting problems. Five are completely free with no account required. The rest are available through a one-time purchase — no subscription, no monthly fee, no tools that stop working if you take a break between books.
The free tools:
- EPUB Validator — checks your EPUB against the same rules KDP, Apple Books, and Kobo use, giving you a prioritized list of errors before you upload
- Metadata Builder — generates properly formatted metadata for KDP, Apple Books, IngramSpark, and Draft2Digital simultaneously from a single form
- Word Cleanup Checker — scans your .docx file for formatting problems (double spaces, straight quotes, stacked blank paragraphs) before conversion
- Cover Checker — verifies your cover image meets every major platform's pixel dimensions, aspect ratio, and file size requirements
- Full Manuscript Mode — converts your .docx or .txt to a valid EPUB 3.0 file with chapter detection, clean HTML, and proper structure in one step
No signup required to use any of these. Open the tool, upload your file or paste your text, get a result.
The Problem We Built This to Solve
Most ebook publishing problems aren't about the writing. They're about the file. Authors finish their manuscripts and then hit a wall of technical requirements: EPUB structure, OPF manifests, table of contents formatting, metadata standards, image size limits, CSS compatibility across devices.
None of this has anything to do with writing a good book. But getting it wrong means KDP rejections, Apple Books rejections, broken formatting on some devices, or a reading experience that undermines the book itself.
The tools that existed to solve this fell into two categories. Expensive paid software like Vellum ($249.99, Mac only) that requires significant investment and platform lock-in. Free manual tools like Calibre and Sigil that are excellent but have steep learning curves and require hours of learning before you can produce reliable output.
We wanted something in between. Tools that do specific jobs automatically, in the browser, without requiring you to learn EPUB internals or pay monthly for software you only need occasionally.
A Quick Walkthrough: Getting From Manuscript to Published
Here's the typical flow for an author using BookKraft AI to take a finished manuscript to a published ebook:
Step 1: Clean the manuscript. Upload your .docx to the Word Cleanup Checker. Review the report — double spaces, straight quotes, stacked blank paragraphs. Make corrections in Word and download the cleaned file. This step prevents most EPUB conversion errors before they happen.
Step 2: Convert to EPUB. Upload the cleaned manuscript to Full Manuscript Mode. It detects chapter headings automatically, builds clean EPUB 3.0 HTML, generates the OPF manifest and nav document, and returns a valid EPUB file in about 30 seconds.
Step 3: Build metadata. Fill in your book's information once in the Metadata Builder. Get correctly formatted metadata for every platform at once — paste the EPUB OPF metadata directly into your package file.
Step 4: Validate. Upload the EPUB to the EPUB Validator. Review the report. Fix any issues the validator flags, re-upload to confirm zero errors.
Step 5: Check your cover. Upload your cover image to the Cover Checker. It verifies dimensions, aspect ratio, and file size against every major platform's requirements.
Step 6: Publish. Upload your validated EPUB to KDP, Apple Books Connect, Kobo Writing Life, or any other platform.
That's the full workflow. Zero paid software. Zero installation. For most prose books, it takes under an hour from cleaned manuscript to publish-ready EPUB.
What Makes BookKraft AI Different
Three decisions shaped how we built these tools:
Everything runs in the browser. No downloads, no installation, no Mac-only restriction. The free tools process files entirely in your browser using JavaScript — your manuscript never leaves your device. The AI-powered tools send text to the AI for processing but don't store it after the session ends.
One-time pricing. If you buy a Starter or Pro plan, you have those tools permanently. No subscription that expires if you take six months off between books. No tiers that lock features you actually need behind higher-priced plans.
Free tools that are genuinely useful. The EPUB Validator, Metadata Builder, Cover Checker, Word Cleanup Checker, and Manuscript Mode are all free — not limited trial versions. We make the free tools as good as the paid ones because the right approach to validation and conversion shouldn't cost money.
Common Use Cases
"My EPUB was rejected by Apple Books but works on KDP." This is the most common scenario we handle. Run your EPUB through the validator — it shows the exact errors Apple Books found, which KDP silently ignored by converting the file before publication.
"KDP says 'No TOC Found' but I have a table of contents." The TOC exists in the visible content but isn't structured as a proper EPUB navigation document. The TOC Generator rebuilds it correctly from your chapter headings.
"I need to publish to five platforms at once." The Metadata Builder generates platform-specific metadata for all of them from one form. Pair it with a validated EPUB and you have everything you need for simultaneous wide distribution.
"My manuscript is a mess of Word formatting." The Word Cleanup Checker shows you exactly what to fix before conversion. Fix it in Word first, then convert — the resulting EPUB will be clean on the first pass instead of requiring multiple rounds of fixes.
Pro Tips for New Users
- Always validate before uploading anywhere. A quick validation run is the single most valuable habit in ebook publishing. It catches rejections before they happen and saves days of back-and-forth with platform support.
- Clean before converting. Garbage in, garbage out. A clean manuscript produces a clean EPUB. Trying to fix EPUB errors that originated in a messy Word document is always harder than fixing the source file first.
- Fix all errors, not just the ones that caused the rejection. When you get a KDP or Apple Books rejection, fix everything the validator reports — not just the specific error in the rejection email. Submitting an EPUB that still has other issues will just generate another rejection cycle.
Get Started
If you have an EPUB getting rejected, start with the EPUB Validator. Free, 30 seconds, tells you exactly what's wrong.
If you're formatting from scratch, start with Full Manuscript Mode — upload your manuscript and get a valid EPUB back in one step.
Everything else is on the dashboard when you create an account. The free tools don't need an account at all.
Frequently Asked Questions
Is BookKraft AI free?
Five core tools are completely free with no account required: EPUB Validator, Metadata Builder, Word Cleanup Checker, Cover Checker, and Full Manuscript Mode. Additional AI-powered tools are available through a one-time Starter or Pro plan — no subscription, no recurring charges. You pay once and use the tools for as long as you need them.
Do I need to create an account to use the free tools?
No. All five free tools work immediately with no signup. An account is only needed if you want to save your work history, access the dashboard, or use the paid AI-powered tools. You can validate EPUBs, clean manuscripts, check covers, and build metadata entirely without creating an account.
Does BookKraft AI store my manuscripts?
The free tools process files entirely in your browser using JavaScript — nothing is uploaded to our servers. Your manuscript stays on your device. The AI-powered tools send your text to our AI provider for processing but don't store it after the session ends. Our full privacy policy is at bookkraftai.com/privacy.
What ebook formats does BookKraft AI support?
The core output format is EPUB 3.0, the industry standard for ebook distribution supported by Apple Books, Kobo, Google Play Books, IngramSpark, Draft2Digital, and most other platforms. The metadata tools output formatted data for KDP specifically as well. For print book interiors, you'll still need to submit PDF directly to KDP or IngramSpark — the tools focus on ebook (EPUB) formatting, not print layout.
How is BookKraft AI different from Vellum, Atticus, or Calibre?
Vellum is Mac-only desktop software focused on print and ebook design — it produces beautifully designed ebooks but requires a Mac and a $249.99 purchase. Atticus is cross-platform desktop software with a writing environment built in. Calibre is a free desktop application with powerful conversion capabilities but a significant learning curve. BookKraft AI is web-based, works on any device, and focuses on technical correctness and compliance rather than visual design. Many authors use BookKraft AI alongside Vellum or Atticus — using it for validation and metadata while using the design tool for layout.