Getting words down
ProseEngine
A fiction studio for drafting and revising a novel in one project: inline rewrites, a story codex, continuity checks, and scene scoring. You can bring an API key or use prepaid credits. The free plan is narrow, and a score is not the same thing as taste.
Best for
Fiction writers who want continuity checks and rewrite tools on their own manuscript, not a general-purpose chatbot.
Pricing
Freemium. Free plan with tight AI limits. Paid subscriptions (publicly listed from €9/month) include a credit allowance, or you can bring an API key.
Listing checked 14 October 2026. Plans move. The vendor's page wins an argument with this one.
The person who keeps this directory also builds ProseEngine. It is listed on the same terms as every other tool. This page is not a promotion, and the card on the home shelf is the same size as the others.
In-depth review
ProseEngine review
Last checked 14 October 2026 against the vendor's public pages. Prices and features change; check the vendor before you buy.
Disclosure: The person who runs Writer's Toolbelt also makes ProseEngine, an AI fiction-writing app that competes with ProseEngine. This review sticks to verifiable facts and links its sources below.
Writer's Toolbelt review
ProseEngine
A fiction writing studio with a story codex, scene generation, 14 craft metrics and bring-your-own-AI. Made by the person who runs this site.
- Free plan, no time limit
- craft metrics (vendor figure)
- AI models to choose from (vendor figure)
We don't score ProseEngine. The person who runs Writer's Toolbelt also builds ProseEngine, so an editorial score here would not be independent. This page sticks to what the product's own site says and points you to comparable tools.
What it is
ProseEngine describes itself as an "AI Writing Studio for Fiction Authors". According to its site, "the AI writes full scenes that follow your story bible — your characters, your world, your established facts — and 14 craft metrics show you exactly what's working." It covers drafting, AI editorial feedback ("AI reads every scene like a professional editor — pacing, tension, dialogue, voice"), and export to DOCX, EPUB or PDF, with a multi-voice audiobook option.
Who it's for
The site addresses novelists who say things like "I've finished my draft but I have no idea where to start revising", "Every time I rewrite a chapter, I break something else", and "I'm writing a series and I can't keep track of my own world anymore". In practice that means:
- Novelists in revision who want scene-level feedback.
- Series authors who need a codex and continuity checks.
- Writers who want control over AI costs through their own key, a free model or local models.
Key features in practice
According to the plan table on the site:
- In every plan: unlimited scenes, Story Codex and Relationship Web, cloud sync (Drive, OneDrive, Dropbox), charts and dashboards, named versions with diff, Scene Finder, Focus Mode and DOCX export.
- Inline AI tools (Rewrite, Tone, Describe and others): 3 runs per book on Free, unlimited on paid plans.
- AI chat, scoring and book reviews: metered on Free, unlimited on paid plans.
- Continuity. An AI continuity checker and a whole-book continuity check.
- Pro generation (Author and up): scene and full-book generation, "AI canon enforcement + quality gate", Suggest Next Scene, Author Packs, Metrics Compare.
- Studio tools: Character DNA and deep analytics, AI chart insights, multi-voice audiobook, co-author collaboration.
- Exports: DOCX on Free, EPUB/PDF and a Story Bible on Writer, and "print-ready" on Author and Studio.
How the AI is paid for
The site offers three ways to power the AI, on any plan: bring your own key from OpenAI, Anthropic, Google or others ("we add no margin"); connect a free or local model, for example Google's free Gemini tier ("your AI cost is literally zero"); or prepaid Managed AI credits ("an upfront markup"). Paid plans include a monthly AI credit allowance of US$10, $20 or $30, and the site says it offers 40+ models.
Pricing (checked 14 October 2026)
| Plan | Monthly | Yearly | Includes |
|---|---|---|---|
| Free | €0 forever | — | 3 books, 2 drafts, full editor, first AI scene free |
| Writer | €9/month | €8/month (€99/yr) | Unlimited AI editing on your own prose, US$10 AI credits |
| Author | €19/month | €16/month (€190/yr) | Scene and full-book generation, US$20 AI credits |
| Studio | €29/month | €22/month (€261/yr) | Deep analytics, audiobook, co-authors, US$30 AI credits |
The FAQ says the free tier needs no credit card and has no time limit.
Pricing at a glance
Billed monthlyBilled yearly
- Free3 books, full editor, metered AIFree
- WriterUnlimited AI editing; US$10 AI credits/mo€9/mo€8/mo
- AuthorScene and full-book generation; US$20 credits€19/mo€16/mo
- StudioDeep analytics, audiobook, co-authors; US$30 credits€29/mo€22/mo
Using it as a writer
- Start on Free with one book. Import or write a few scenes and fill in the Story Codex.
- Try the free AI scene and the metered scoring to see whether the feedback style suits you.
- Decide how you want to pay for AI, whether that's your own key, a free model or credits, before upgrading.
- Compare it with alternatives on the same chapter, such as Sudowrite and Novelcrafter, and choose on output, not on our word.
Strengths (as presented by the vendor)
- A permanent free plan.
- Flexible AI sourcing, including free and local models.
- Revision analytics (14 craft metrics) alongside drafting.
- Exports up to print-ready, plus an audiobook option.
Things to weigh
- Feature-gating is detailed. Many tools are "1 try per book" below Author or Studio, so read the plan table.
- AI costs depend on your setup when you use your own key.
- A young product compared with long-established tools. Weigh that against the free plan.
How it compares
- ProseEngine vs Sudowrite. Sudowrite bundles credits and its own fiction models. See our Sudowrite review.
- ProseEngine vs Novelcrafter. Novelcrafter is also bring-your-own-key, with a deep codex. See our Novelcrafter review.
- ProseEngine vs NovelAI. NovelAI focuses on exploratory co-writing and anime art.
Feature comparison
AI fiction drafting tools compared
| Feature | NovelAI | Squibler | Type.ai | Storysnap | ProseEngine |
|---|---|---|---|---|---|
| Free plan | Yes | Yes | Yes | No | Yes |
| Lowest listed paid price | Yes$10 | Yes$15.83 | Yes$8 | Yes$45 | Yes€8 |
| All paid tiers have published prices | Yes | Yes | Yes | Yes | Yes |
| Competes with ProseEngine (we disclose) | Yes | Yes | Yes | Yes | Yes |
Bottom line
Because of the conflict of interest, we give no verdict here. Try the free plan alongside the alternatives above and judge for yourself.
FAQ
Is ProseEngine free? There is a free plan with no time limit and no credit card.
Do I need an API key? Not to start. The site says you can bring your own key, use a free or local model, or buy prepaid credits.
Who makes ProseEngine? The same person who runs Writer's Toolbelt. That's why this page has no scores.
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