Questions writers actually ask.

You can start on one. Two engines sign in without paying anybody: ChatGPT works with any account, the free one included, and Gemini works on Google's free tier. Claude needs a Pro or Max plan, and Grok needs X Premium+ or SuperGrok. Know how far that carries, though. Free plans come with small usage limits and a real drafting session reaches them quickly — enough to try the co-writer, thin for writing a whole book on. The way to write all day without paying anyone is a local model through Ollama or LM Studio, where there is nothing to pay and no usage limit at all, though you will want a powerful computer to run one well.

Yes. No engine requires one, since signing in the way you always sign in is the ordinary path, but if you would rather run the co-writer on your own key, Proselon accepts that too, whether from OpenRouter, xAI, or any OpenAI-compatible endpoint. You pay the provider directly at their rates, with no markup and no second meter from us. Everything else about the app behaves identically.

Yes. Ask within 30 days of a charge and you get it back. No reason needed, no form, no retention script. Email us and we reverse it. Surprise charges are hard to come by in the first place, since the 30-day trial takes no credit card, we email you before your first charges, and cancelling is one click from your billing portal. Whatever happens with the billing, your manuscript is plain files in your own Documents folder, and a refund never touches your book.

Your book was never ours to hold. It lives as a folder of plain files in your own Documents, written the way you wrote it, and it stays there whether you cancel tomorrow or we close the company. There is no server to retrieve it from, and no window in which to rescue it before something deletes it. There is an Export button in the app, which will hand you the book as Word for Vellum, EPUB for reading apps, HTML for posting online, or a single plain-text file. That is a convenience rather than an escape route. Delete the application and every chapter is still on your disk, readable in any editor you like, beside the version history that recorded how it got there. We keep nothing of yours, so there is nothing of yours for us to lose.

Never by us. Proselon does not collect your book, so there is nothing of yours on our side to train on. The consequential question is the engine. What you send the co-writer goes to the AI you chose, under your own account, and each provider sets its own training policy, ordinarily a setting in your account there and often different by plan. Free tiers are likelier to train on conversations, paid and business plans less so. It is the same policy that already governs your direct chats with that AI, so check the setting once and it covers both. Where the answer has to be a flat no, run a local model through Ollama or LM Studio. It learns nothing and sends nothing anywhere.

Yes, though it was not designed for that. Proselon is meant to sit beside you while you write, which is a different thing from writing in your place. Even so, nothing prevents it. Give the co-writer a premise and whatever specifications matter to you, and it will write the whole book to them. We did precisely that several times while testing the application, and some of what came back was a pleasure to read. Most writers will want something well short of a book produced at a prompt, and the same application covers the ground between. A scene you rough out and hand over to be finished, or a chapter you wrote alone and want read back with an editor's eye — Proselon does either, and the proportion is yours to set. You can change it from one chapter to the next.

Yes, though this is not legal advice and ought to be taken as orientation rather than counsel. In the United States copyright protects human authorship, and the question has never been whether AI was involved but what you contributed. Everything you wrote, and everything you substantively rewrote in your own words, is yours, and so is the shape of the book — your plot, your characters, the selection and arrangement of the whole. What does not qualify is prose you prompted and kept as it arrived, and on registration you are required to disclose AI-generated material and leave it out of the claim. This is among the reasons Proselon keeps a complete version history of your book. It amounts to a dated, continuous record of the drafting and revision, in a standard open format sitting in your own folder, which you can hand to a lawyer should your authorship ever be questioned. The long version, including where the Supreme Court left the law in March 2026 and what it means at each level of AI use, is in our guide to copyright for AI-assisted novels.

Yes. A fanfic is a book like any other so far as Proselon is concerned, and the long serial, which is fandom's native form, is precisely the case it was built for. The co-writer reads what it needs from your chapters rather than attempting to hold the whole thing in its head, and the Story State ledger keeps the details straight at chapter one hundred. Your writing lives as plain files on your own computer, and we place no restrictions on what you write.

Proselon itself places no restrictions on your writing. No filters, no scanning, no content rules. Your files are yours, on your own computer. The co-writer is where it depends. The signed-in engines, which is to say Claude, ChatGPT, Grok and Gemini, apply their own content policies exactly as they do when you chat with them directly, so mature themes are ordinarily fine while fully explicit scenes vary by provider. If you want a co-writer bound by no such rules, run a local model through Ollama or LM Studio. You pick the model, its limits are the only limits, and nothing leaves your machine.