Lacuna — Desktop-Native Book Formatting for Windows and Mac

Lacuna (lacuna.pub) is a book formatting application for Windows and Mac that turns your Word document into a professionally formatted book — print-ready PDFs for paperback and hardcover, and EPUB files for ebook distribution. It's desktop-native, meaning it installs on your computer and works completely offline. Your files stay on your machine, not on someone else's server.

Lacuna was built by a brother-sister team: Melissa, a published indie author with over twenty years of writing experience and fourteen books in print, and Corey, a software developer with twenty-five years of coding experience. The origin story matters here — Melissa needed better formatting software and couldn't find it, so Corey built it. The result is a tool designed by someone who actually formats books for publication, not by engineers who've observed the process from a distance.

Who Lacuna Is For

Lacuna occupies a specific and well-defined place in the formatting tool landscape:

• Windows authors who want formatting output quality comparable to Vellum — Vellum is Mac-only; Lacuna fills that gap specifically

• Authors on any platform who want desktop-native software — Lacuna installs on your computer and works offline, unlike Atticus (browser-based, files on their servers) or Ulysses (cloud-based)

• Authors with a DOCX-based workflow — Lacuna's import is built around Word documents, automatically detecting chapters and sections from your heading structure

• Authors who value file privacy — Lacuna's files live on your computer, not on a company's server, which matters for authors who are cautious about AI training data and content privacy

• Authors formatting non-fiction, academic books, or illustrated books — Lacuna's support for footnotes, endnotes, tables, images, call-out boxes, and text conversations gives it broader structural capability than some fiction-focused tools

Platform Compatibility and Pricing

The free trial structure deserves emphasis: every feature in Lacuna is fully available during the trial period — you can import your manuscript, apply styles, customize every setting, and see exactly what your formatted book will look like — and the only thing locked behind the purchase is the actual EPUB and PDF export. There's no time limit and no credit card required to download and try it. This is a genuine try-before-you-buy model, not a feature-stripped demo.

🔗 https://lacuna.pub

The Core Workflow

Lacuna's workflow is deliberately straightforward: import your DOCX file, let Lacuna detect and organize your chapters, apply a style, customize as needed, and export.

Step 1: Import Your DOCX

Lacuna imports your manuscript from a Word document (.docx). The smart import automatically detects your chapter breaks based on the heading styles in your document — this is why applying proper Heading styles in Word during drafting matters, as covered in the Microsoft Word article. Chapters, parts, front matter, and back matter are identified and organized into Lacuna's project sidebar automatically. Authors who've been using Word with proper styles find their manuscript lands in Lacuna already organized; authors who formatted manually may need a few minutes of cleanup.

Step 2: Choose and Customize a Style

Lacuna includes professionally designed style presets — typographic templates that control chapter heading appearance, body text formatting, first paragraph treatment, drop caps, indentation, ornamental breaks, and more. Each element is independently customizable: you can accept a preset's overall aesthetic and adjust specific elements (change the drop cap behavior, modify heading spacing, adjust indentation) without rebuilding from scratch. This gives you more granular control than Vellum's theme system, while remaining approachable for authors without design experience.

Section-level style overrides let you apply different formatting to specific sections — useful for books with mixed content types, or for making front matter and back matter look distinct from the main chapters.

Step 3: Export

Lacuna exports to EPUB 3 and EPUB 2 for ebook distribution, and PDF/X-1a for print. PDF/X-1a is the print-ready format KDP Print and IngramSpark require — Lacuna's print PDFs are configured for these platforms' specifications by default, including appropriate bleed, gutter, and margin settings for standard trim sizes.

Key Features

Footnotes and Endnotes

As of May 2026, Lacuna natively supports both footnotes and endnotes — endnotes specifically being a recent addition. This matters for non-fiction authors, academic writers, and any author using reference material that requires footnoting. Configure endnotes settings in Edit Styles > Endnotes Settings, and add an Endnotes section to your back matter or automatically append them to individual sections. This is a feature set that fiction-focused formatting tools often lack entirely.

Kobo-Specific EPUB Export

Lacuna added a Kobo-specific EPUB export option in the May 2026 update. When exporting EPUB files, you can now select a device type that generates a Kobo-optimized file improving the reading experience specifically on Kobo devices — addressing the formatting differences between Kobo's reader and generic EPUB display. For wide-publishing authors distributing through Kobo directly or through Draft2Digital, this means a cleaner reader experience without manual workarounds.

Full-Page Images and Image Gallery

Lacuna supports full-page images, inline images with text wrap, and an image gallery feature. Chapter header images can be added to style the opening of each chapter. Image captions are separately styleable. For illustrated books, children's books with images, or non-fiction with figures, this capability puts Lacuna ahead of formatting tools that treat images as an afterthought.

Tables, Lists, Blockquotes, and Call-Out Boxes

Beyond prose fiction, Lacuna handles structural elements that non-fiction, academic, and hybrid books require: tables, ordered and unordered lists, blockquotes, call-out boxes, and footnotes/endnotes. Text conversations — a layout type for showing phone or messenger exchanges — are also supported, useful for contemporary fiction with this kind of content. This breadth makes Lacuna a genuinely versatile formatting tool rather than one optimized exclusively for straightforward prose novels.

Drop Caps and First Paragraph Styling

Drop caps — the enlarged first letter at the start of a chapter — are a style-level setting in Lacuna, applied consistently across all chapters once configured. First paragraph styling (the formatting of the first paragraph of each chapter, often set differently from body paragraphs in traditional typography) is independently controllable. Both are accessible without CSS knowledge or manual per-chapter work.

Device-Specific Sections and Blocks

Lacuna supports content that displays only in specific contexts — sections or blocks that appear in the EPUB but not the print PDF, or vice versa. This is particularly useful for back matter: a "Buy my other books" link that's live and clickable in the ebook but formatted differently or omitted in print, or a print-specific page with different layout requirements than the ebook equivalent.

Desktop-Native, Offline, and Private

Lacuna is installed on your computer and runs entirely offline. Your manuscript files are stored on your machine, not on Lacuna's servers. This has practical implications: you can format a book on an airplane, in a location without reliable internet, or in any circumstance where cloud-based tools would be unavailable. It also has a content-privacy implication that Lacuna's own comparison pages emphasize: browser-based tools store your manuscript on their servers, which raises questions about AI training and data privacy that some authors care about. Desktop-native tools have no equivalent concern.

How Lacuna Compares to Vellum and Atticus

The comparison points to Lacuna's positioning: it's a formatting-only tool (like Vellum) that works on both platforms (unlike Vellum), runs offline with local file storage (unlike Atticus), and costs less than both while supporting a broader range of structural elements. The tradeoff: no integrated writing environment, so you're bringing your DOCX from Word or Scrivener.

The Origin Story and What It Means for the Tool

Most formatting software is built by developers who observe author pain points from outside the process. Lacuna is different in a specific way: Melissa, the co-creator who defined what the tool needed to do, is an active indie author who has formatted her own books for publication for years. The features Lacuna prioritizes — DOCX import that actually works cleanly, per-section style overrides, footnotes and endnotes, Kobo-specific output — reflect the specific frustrations of an author who needed them, not a product manager's estimate of what the market wants.

The "no investors, just a family business" framing on Lacuna's site isn't marketing language — it reflects a genuine difference in how the tool is developed. Updates are driven by what the team and their author community actually need. The May 2026 endnotes and Kobo EPUB updates are good examples: both are responses to specific user requests that a traditionally funded software company might have deprioritized for quarters.

ScribeCount Author OS — Tracking Your Lacuna-Formatted Books

After formatting in Lacuna and publishing to KDP, Kobo, Apple Books, IngramSpark, or your direct store, ScribeCount's Sales Dashboard tracks your book's performance across every platform you distribute to. For wide-publishing authors who use Lacuna's Kobo-specific EPUB export, ScribeCount shows Kobo income alongside every other platform — so you can see whether that platform-specific optimization is translating into better Kobo sales without having to check Kobo's dashboard separately.

Conclusion

Lacuna is a well-designed, actively developed desktop formatting tool that fills a genuine gap — giving Windows authors access to formatting quality that was previously only available on Mac, while offering Mac authors a desktop-native alternative to Vellum at a lower price with broader structural capability.

Its unlimited free trial is one of the most honest trial models in the category: format your entire book, see exactly what the output looks like, and only pay when you're ready to export. At $139 one-time with lifetime updates, local file storage, and full offline capability, it's positioned as both a more accessible and a more private option than the browser-based alternatives.

For authors whose workflow is DOCX-in, formatted-book-out — and that's most authors — Lacuna delivers on that workflow cleanly and at a price that makes it worth trying alongside whatever tool you're currently using.

— Randall