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Comparison

kdpbook.io vs Sudowrite: an honest comparison

Sudowrite is an AI writing partner for fiction, from $10/month billed yearly ($19 monthly): Story Bible, Write, Describe and Rewrite help you draft in your own voice. Its export docs list .docx files, so the print layout, cover and eBook are made in other tools. kdpbook.io writes the novel or imports yours, then exports the interior PDF, full-wrap cover and Kindle EPUB.

By kdpbook.io editorialPublished

We make kdpbook.io, so we’re not neutral. Everything about Sudowrite below comes from its public pages as of (linked at the end); prices and features may have changed since.

At a glance

kdpbook.io compared with Sudowrite
Criterionkdpbook.ioSudowrite
Main jobWrites and illustrates the book, or lays out your own manuscript, then builds the KDP filesHelps you write fiction: drafting, description, rewriting and feedback, in your voice
Writing the bookPlans and writes the whole book from one chat (a novel runs 55,000–120,000 words), or imports your manuscriptYou lead: Story Bible goes from idea to outline to chapter beats to thousands of words, Expand turns an outline into a rough draft, Write suggests the next 300 words
EditingPage editor with live preview, AI rewrites and image redrawsRewrite, Describe, Expand and Feedback on selected text; developmental edits, line edits and beta reads on Professional and Max
OutputInterior PDF, full-wrap cover PDF, Kindle EPUB + Kindle cover, and a KDP listing sheet.docx (one document or the merged project), a .zip of documents, Story Bible sections as .csv
Print interiorTrim, bleed, margins, spine and page limits applied automatically, with a preflight checkNot documented: its export docs list no PDF
CoverFull-wrap cover PDF sized from trim, paper and final page countNot documented
Kindle eBookKindle EPUB (reflowable or fixed layout) + Kindle coverNot documented: its export docs list no EPUB
Images40 illustration styles or your own; character reference sheets reused on every illustrationVisualize: 1,024 × 1,024 px images from a passage, 2,500 credits each (about 3.41 in wide at 300 DPI)
Languages34 KDP-supported languages30+ languages, per its pricing page; its FAQ says features other than Write may fall back on English
PlatformsWeb app in the browserWeb app, plus iOS and Android apps (new Visualize images are web only)
PricingFree: 2,000 credits once, no card. Plans $25–$99/month$10–$44/month billed yearly, $19–$59 monthly

  • Main job

    kdpbook.io
    Writes and illustrates the book, or lays out your own manuscript, then builds the KDP files
    Sudowrite
    Helps you write fiction: drafting, description, rewriting and feedback, in your voice

  • Writing the book

    kdpbook.io
    Plans and writes the whole book from one chat (a novel runs 55,000–120,000 words), or imports your manuscript
    Sudowrite
    You lead: Story Bible goes from idea to outline to chapter beats to thousands of words, Expand turns an outline into a rough draft, Write suggests the next 300 words

  • Editing

    kdpbook.io
    Page editor with live preview, AI rewrites and image redraws
    Sudowrite
    Rewrite, Describe, Expand and Feedback on selected text; developmental edits, line edits and beta reads on Professional and Max

  • Output

    kdpbook.io
    Interior PDF, full-wrap cover PDF, Kindle EPUB + Kindle cover, and a KDP listing sheet
    Sudowrite
    .docx (one document or the merged project), a .zip of documents, Story Bible sections as .csv

  • Print interior

    kdpbook.io
    Trim, bleed, margins, spine and page limits applied automatically, with a preflight check
    Sudowrite
    Not documented: its export docs list no PDF

  • Cover

    kdpbook.io
    Full-wrap cover PDF sized from trim, paper and final page count
    Sudowrite
    Not documented

  • Kindle eBook

    kdpbook.io
    Kindle EPUB (reflowable or fixed layout) + Kindle cover
    Sudowrite
    Not documented: its export docs list no EPUB

  • Images

    kdpbook.io
    40 illustration styles or your own; character reference sheets reused on every illustration
    Sudowrite
    Visualize: 1,024 × 1,024 px images from a passage, 2,500 credits each (about 3.41 in wide at 300 DPI)

  • Languages

    kdpbook.io
    34 KDP-supported languages
    Sudowrite
    30+ languages, per its pricing page; its FAQ says features other than Write may fall back on English

  • Platforms

    kdpbook.io
    Web app in the browser
    Sudowrite
    Web app, plus iOS and Android apps (new Visualize images are web only)

  • Pricing

    kdpbook.io
    Free: 2,000 credits once, no card. Plans $25–$99/month
    Sudowrite
    $10–$44/month billed yearly, $19–$59 monthly

What Sudowrite is

An AI writing app for fiction, on the web with iOS and Android apps. Story Bible takes a book from idea to outline to chapter beats; Write suggests the next 300 words in your voice; Describe, Expand, Rewrite and Feedback work on the passages you select; Visualize turns a description into an image. It runs its own fiction models (Muse and Ballad) alongside 30+ others, including Claude and OpenAI models, and exports your documents as .docx.

Where it shines

  • Prose tools made for fiction: Write continues in your voice, Describe adds vivid description, Expand fleshes out a rushed scene, Feedback names five areas to improve.
  • Story Bible keeps characters, worldbuilding and the outline in one place, with continuity tools for a series.
  • Its own fiction models (Muse and Ballad), plus 30+ other models to choose from.
  • Its FAQ says it claims no rights over what you write or generate, and doesn't use your writing to train its models or OpenAI's.
  • Mobile apps for iOS and Android, and a free trial without a card.

Sudowrite pricing

  • Hobby & Student $10/month billed yearly or $19 monthly (225,000 credits a month); Professional $22 or $29 (1,000,000 credits, adds developmental edits, line edits and beta reads); Max $44 or $59 (2,000,000 credits that roll over for 12 months).
  • Credits don't map to words: its docs say 1,000,000 credits can produce 50,000 to 500,000 AI words a month, depending on the model and how much text it reads. Visualize costs 2,500 credits an image.
  • Free trial: 10,000 credits, no card. The monthly prices and the trial come from its blog (updated July 13, 2026); its pricing page shows the yearly prices.

As published on September 28, 2026. See the current prices on its website.

Which one should you choose?

Choose Sudowrite if…

  • You want to write the novel yourself, with AI help on prose, pacing and description.
  • You write a fiction series and want a Story Bible and continuity tools across books.
  • You already format elsewhere (Atticus, Vellum, Kindle Create) and only need help writing.

Choose kdpbook.io if…

  • You want the finished KDP files, not only the manuscript: interior PDF, full-wrap cover, Kindle EPUB and a listing sheet with 7 keywords.
  • You drafted in Sudowrite and want the book laid out: export one merged .docx, import it, and your words are set as written.
  • You make more than fiction: picture books, non-fiction, cookbooks, coloring and puzzle books.

Questions

Is kdpbook.io a Sudowrite alternative?

For some authors. Sudowrite is a writing partner: you stay the author while it drafts, describes and rewrites with you, then you export .docx. kdpbook.io writes the whole book or imports yours and builds the KDP files; a 336-page novel (about 80,000 words) is estimated at about 5,377 credits (≈ $54), interior, cover and Kindle file included. If you want to write every scene yourself, Sudowrite is the better fit, and the two work together.

Can I lay out a Sudowrite manuscript for KDP with kdpbook.io?

Yes. Export the project from Sudowrite as one merged .docx (its docs note that the Story Bible isn't included) and import it into a novel or another text book type: 19 of the 36 types accept an import. Words, punctuation and line breaks inside paragraphs are kept. Reading the manuscript costs 3 credits per 1,000 words, and the book's estimate (plan, layout, cover art) is shown before you launch.

Do I have to disclose AI on KDP if I write with Sudowrite?

It depends on who wrote the words. KDP treats text created by an AI tool as AI-generated, even after substantial edits, and asks you to disclose it when you publish or republish; text that Write or Expand produced falls under that. AI used only to edit, refine, error-check or brainstorm your own writing counts as AI-assisted and doesn't need disclosure. kdpbook.io's listing sheet pre-fills the disclosure answers from how much of the text and art its AI made.

Sources · read on September 28, 2026

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