AI story generators for adults: seven tools, checked against their own pages
By Edgar A.7 min read
Adults who want an AI story generator usually want two things: a tool that will write mature fiction without a lecture, and one that writes it well. Those are separate questions. This comparison covers seven products, with every fact taken from each product’s own public pages as they stood in November 2026, and it says plainly where those pages left a gap.
How these were checked
For each product, the home page, the pricing page and, where one exists, the terms or content guidance were read in November 2026. Prices are the listed monthly prices at that time, in US dollars, and they change often. Nothing here is a test of prose quality. It is what each company says about itself, set side by side.
This site’s own NSFW story generator is left out of the table on purpose. A site should not grade itself.
The seven at a glance
| Tool | What it is | Listed price | Mature content | Where stories live |
|---|---|---|---|---|
| NovelAI | Story writer and anime image tool | Free tier; $10, $15 or $25 a month | Its terms set no rule on mature text either way | Encrypted on its servers |
| Sudowrite | Drafting suite for novelists | Free trial; $10, $22 or $44 a month billed yearly, $19, $29 or $59 monthly | Set per model; its own Muse model is the least filtered | Not stated |
| NovelCrafter | Planning and writing app, bring your own AI | 21-day trial; $4 to $20 a month | Depends on the model you connect | Not stated |
| AI Dungeon | Text adventure and story game | Free tier; paid tiers $14.99 to $99.99 a month | Three safety levels; Mature asks you to confirm you are 18, and an under-18 filter stays on | Not stated |
| Perchance story generator | Free page that writes paragraph by paragraph | No price listed; funded by ads | Follows adult prompts when asked, per its notes | Your browser only |
| KoboldCpp | Open-source program that runs a model on your computer | Free; you supply the model and hardware | Whatever the model you load allows | Your computer |
| Venice | AI chat with text and image models | Free with 10 text prompts a day; Pro $18 a month | Every plan listed as private and uncensored | Local storage listed |
NovelAI
The home page presents NovelAI as an anime-style image generator and a story writer in one subscription, and names GLM 4.6 as the model behind the stories. Its documentation lists a free tier of 50 text generations once you verify an email address, then Tablet at $10, Scroll at $15 and Opus at $25 a month. The terms require users to be 18 or older, set no rule on mature text either way, and say stored content is encrypted with a key tied to your login, so a lost password means lost stories. The pricing page returned an error, so prices come from the documentation.
Sudowrite
Sudowrite is built for novelists. Its Story Bible walks a book from idea to outline to chapter beats, and Write suggests the next 300 words in your voice. Plans were $10, $22 and $44 a month billed yearly, or $19, $29 and $59 billed monthly, each with a free trial and no card required. Its documentation rates every model’s filtering: the in-house Muse model is the least filtered, Claude models sit in the middle, and the Basic option on GPT-4o Mini is strict. The FAQ says it does not train models on your writing and claims no rights over what it generates for you.
NovelCrafter
NovelCrafter is built around the Codex, a story bible for characters, places and lore that links itself as you write. It brings no model of its own. On the paid plans you connect your own key for OpenAI, Anthropic, Google, Mistral or OpenRouter, or run a local model through LM Studio or Ollama. Plans run from $4 (no AI features) through $8 and $14 to $20 a month, after a 21-day trial without a card. Its romance page says moderation depends on the model you pick, and Codex entries can be flagged so they only reach prompts you mark as NSFW.
AI Dungeon
AI Dungeon is a story game more than a manuscript tool: you pick or build a scenario and make choices as the story unfolds. Its help pages describe three safety levels. Safe blocks mature material, Moderate reduces it, and Mature lifts those limits but asks you to confirm you are 18 or older. A filter for content involving anyone under 18 stays on at every level, and the page admits it sometimes misfires.
The membership help page lists a free tier with up to 4k tokens of context and paid tiers from $14.99 to $99.99 a month, with more memory at each step. The pricing page itself did not load its plans when checked.
Perchance
The Perchance story generator writes a long story paragraph by paragraph from an overview and instructions you give it, and inserts summary paragraphs as it grows to stretch the AI’s memory. Stories live in your browser’s storage, not on a server, so clearing site data deletes them; the page tells you to export backups. The AI plugin behind it is paid for by ads shown to visitors who are not logged in. Its notes say prompts and replies are not stored on the server, and that the model will write adult themes when prompted for them.
KoboldCpp
KoboldCpp is free, open-source software under the AGPL v3 licence that runs a language model on your own machine. It is a single program with no installer, with builds for Windows, Linux and Apple Silicon Macs, and it serves a web interface at localhost:5001 with story, adventure, chat and instruct modes. Models are not included. You download one in the GGUF format yourself, and what it will write depends on that model. Nothing has to leave your computer unless you connect an outside service.
Venice
The pricing page for Venice lists a free plan with base models, 10 text prompts and 15 image prompts a day, then Pro at $18 a month with unlimited text prompts, Pro Plus at $68 and Max at $200. Every plan is described as private and uncensored, and local-only conversation storage appears among the privacy features, though the grid showing which plans include it did not render. Its terms describe a mature content filter and bar users under 18 from switching it off. The home page timed out, so nothing here comes from it.
How to choose between them
Start from what you need, not from the feature lists.
- Privacy first: KoboldCpp keeps everything on your machine, NovelAI encrypts stored stories, and Perchance keeps them in your browser.
- A manuscript with chapters: Sudowrite and NovelCrafter are built around planning and drafting a book.
- Play rather than write: AI Dungeon is a game first.
- Spending nothing: Perchance and KoboldCpp cost nothing, and AI Dungeon, NovelAI and Venice have free tiers with limits.
Then test the finalists with the same premise, and judge them on chapter two rather than chapter one. Almost any tool can open well. The ones that keep threads straight show it in the middle, and the checklist in writing a second chapter doubles as a test.
What could not be verified
- NovelAI: the pricing page returned an error, so its prices come from the documentation.
- Sudowrite: the terms page returned an error, so its content details come from the documentation and FAQ.
- AI Dungeon: the pricing page did not load its plans, so prices come from the membership help page.
- Venice: the home page timed out, and the plan grid for local storage did not render.
- Where stories are stored, for Sudowrite, NovelCrafter and AI Dungeon: not stated on the pages read.
- Prose quality, for all seven. That needs your own premise and an evening.
Questions
Which AI story generators for adults are free?
Perchance and KoboldCpp cost nothing to use. AI Dungeon, NovelAI and Venice have free tiers with limits, and Sudowrite and NovelCrafter offer free trials before a paid plan.
Is a local model more private than an online tool?
Generally yes. With KoboldCpp the model runs on your own computer, so the story stays there unless you choose to connect an outside service yourself.
Do these tools allow mature fiction?
Their pages describe different approaches. Some set the rules per model, some use a safety setting with an age confirmation, and some leave it to whichever model you load.