Why DOCX Only

Ulomira accepts DOCX files exclusively. This is not a limitation—it is an architectural decision.

The Problem We Solve

Most publishing platforms try to accept every file format. They use AI, heuristics, and guesswork to figure out where your chapters begin, which text is a heading, and how your content should be structured.

This creates unpredictable results. Authors upload a file, see something wrong, try to fix it, upload again, and hope for the best. The platform is a black box. You are not in control.

Ulomira takes a different approach.

Structure Is Everything

Ulomira is a structure-first platform. We do not guess at your intent. We read the semantic structure you define in your document and render it exactly.

A Heading 1 becomes a chapter
A Heading 2 becomes a section
A bulleted list becomes a proper list
A code-styled paragraph becomes a code block

What you define is what readers see. No interpretation. No surprises.

Why DOCX Preserves Structure

DOCX files (Microsoft Word, Google Docs, LibreOffice) store paragraph styles as explicit metadata. When you apply “Heading 1” to a line of text, that information is preserved in the file itself.

This means Ulomira can read your document and know, with certainty:

Which paragraphs are chapter titles
Which paragraphs are section headings
Which paragraphs are lists
Which paragraphs are code

There is no ambiguity. The structure is explicit.

Why EPUB Is Not Supported

EPUB is an excellent format for reading. It is not a reliable format for authoring.

When you export a document to EPUB, the export process often loses or flattens structural information. Headings become styled text. Lists become paragraphs with bullet characters. Sections merge together.

This is not a flaw in EPUB—it is simply not what EPUB was designed for. EPUB is an output format, optimized for rendering on e-readers. It was never intended as a source of truth for document structure.

Ulomira could attempt to infer structure from EPUB files, but inference means guessing. Guessing means unpredictable results. We chose not to guess.

Why PDF Is Not Supported

PDF is a page-layout format. It describes where ink goes on paper. It has no concept of “chapter” or “heading” or “list.”

To extract structure from a PDF, a platform must analyze font sizes, spacing, positioning, and visual patterns. This is inherently heuristic. Two PDFs that look identical might produce completely different results depending on how they were created.

PDF is a presentation format. It answers the question “What does this look like?” Ulomira needs to answer the question “What does this mean?”

The Tradeoff

DOCX-only means more work for authors who write in other formats. If you have an existing EPUB or PDF, you cannot upload it directly.

We believe this tradeoff is worth it.

By requiring DOCX, Ulomira guarantees that what you upload is what readers see. You are in complete control. If something looks wrong, you know exactly how to fix it: adjust the styles in your document and re-upload.

This is a publishing platform for authors who care about structure. For technical writers, educators, and anyone who wants predictable, professional results.

A Permanent Decision

This is not a temporary limitation. Ulomira will not add EPUB or PDF support in the future.

DOCX-only is a core architectural decision. It is documented in our internal specifications and reflected in every part of the platform. Changing it would require rebuilding fundamental assumptions about how content flows through the system.

We are confident in this decision because it aligns with our core value: authors control their content.

What This Means For You

If you write in Microsoft Word, Google Docs, or LibreOffice Writer, you are already set. Apply heading styles to your chapter titles, use the built-in list tools, and upload.

If you write in Markdown, Scrivener, or another tool, export to DOCX before uploading. Most writing tools support DOCX export.

If you only have an EPUB or PDF of your book, we recommend returning to your original source document. Converting EPUB/PDF to DOCX often carries over the structural problems that made those formats unsuitable in the first place.

For detailed formatting guidance, see our DOCX Formatting Guide.