ProselonTerms of Service
Last updated 30 July 2026.
1. Who we are, and what you're agreeing to
Proselon is made by Holstein Creations LLC (“we”, “us”). These terms are the agreement between you and us for using Proselon, meaning the macOS and Windows application, this website, and the account service behind them. By creating an account or using Proselon, you agree to them. When you create your account you confirm that agreement with a checkbox, and we record the date and the version of these terms you accepted. If you do not agree, do not use Proselon.
2. Your account
You need an account to use Proselon. Keep your password to yourself. You are responsible for what happens under your account. One account is for one person, and is not to be shared. You must be old enough to enter a contract where you live. We may suspend or close an account that is being used to break these terms or the law.
3. The free trial, pricing, and what happens at the end of the trial
Proselon starts with a 30-day free trial. No payment card is required to begin the trial, and while no card is on file we cannot and do not charge you: if the trial ends without one, it lapses. If you add a card before the trial ends, the plan you chose, at $6.00 per month or $50.00 per year, is charged when the trial ends and renews automatically at the same price until you cancel, and we email you before the trial ends, and again before your first couple of renewals. Subscribing after your trial has ended is charged when you subscribe. Each account gets one free trial. Prices are in US dollars. We may change our prices: if we do, we will email the address on your account before a new price applies to you, and it will apply only from a later renewal, never to a period you have already paid for.
4. Cancelling
You can cancel at any time from the billing portal, which you reach from Settings inside the app or from the link in any billing email you get from us. Cancelling stops future charges. Your plan stays open until the end of the period you have already paid for, and you keep your work either way. Your books are plain files on your own computer, and cancelling does not touch them.
5. Refunds
If you were charged within the last 30 days and would rather not have been, email hello@proselon.com and we will refund that charge. You do not need a reason. The window is a trailing 30 days from the date of the charge; after that the charge is final, though you may cancel at any time so that you are not charged again. We would rather return your money than keep it from someone who does not want the product. This refund promise applies to what you pay us, and does not extend to anything you pay other companies (see section 8).
6. What you may and may not do
Proselon is licensed to you, not sold. You may use it to write. You may not resell it, rent it, redistribute it, reverse-engineer it beyond what the law permits, or use it to produce material that is illegal, or that harasses, defames, or endangers people. We may end your access if you do.
7. Your writing is yours
You own everything you write in Proselon. We claim no rights in it, we do not train anything on it, and we do not store your manuscripts. Your books live as plain files in your own Documents folder on your own computer. Our account service stores only what it needs to run your account (see the Privacy Policy).
8. The AI co-writer runs on your own AI account, and that account is yours to manage
Proselon’s co-writer works through an AI provider you sign into yourself, whether Claude, ChatGPT, Grok or Gemini, or a model you run locally. We do not sell you AI usage, we do not resell any provider’s service, and we do not sit between you and your provider. Your Proselon subscription pays for Proselon, never for AI. Your relationship with your AI provider is entirely your own: their terms govern your use of their service, what they do with what you send them is their policy, and what they charge you is their pricing.
That relationship can change, and the risk of it changing sits with you, not with us. A provider may raise its prices, change what a subscription includes, move features to metered or per-use billing, impose new limits, change its terms, or discontinue a plan or a product entirely, at any time, without our knowledge, and outside our control. If that happens, any new or increased cost is between you and the provider. We do not owe you a refund beyond section 5, a credit, or any other compensation because a provider changed what it offers or what it charges. We may update, replace, or remove Proselon’s integration with any provider in response to changes like these, and doing so is not a breach of these terms.
AI output can be wrong, derivative, or unsuitable. You are the author: every editorial decision is yours, and it is your responsibility to make sure what you publish is yours to publish.
9. Availability
We try to keep Proselon working, but we don’t promise it will be available without interruption, and we may change or discontinue features or the service itself. Proselon also depends on software and services run by others, among them AI providers, hosting and payment processing, and changes or failures there can change or interrupt what Proselon can do. Because your books are plain files on your own machine, you keep them regardless of what happens to the service or to us.
10. No warranty
Proselon is provided “as is”, without warranties of any kind, express or implied, including merchantability, fitness for a particular purpose, and non-infringement, to the fullest extent the law allows.
11. Limit of liability
To the fullest extent the law allows, our total liability to you for any claim relating to Proselon is limited to the amount you paid us in the twelve months before the claim. We are not liable for indirect, incidental, or consequential damages, or for lost profits or lost data. And, as section 8 says, we are not liable for what you pay an AI provider or for a provider’s changes to its service. Some jurisdictions do not allow these limits, in which case they apply to you only as far as the law permits.
12. If your use of Proselon causes a claim against us
If your use of Proselon breaks these terms or the law, and someone else brings a claim against us because of it, you agree to cover the losses, costs, and reasonable legal fees we incur as a result. This does not apply to the extent a claim results from our own breach of these terms.
13. Governing law
These terms are governed by the laws of the State of Ohio, United States, without regard to its conflict-of-laws rules, and the state and federal courts located in Ohio have exclusive jurisdiction over any dispute arising from them.
14. Changes to these terms
We may update these terms. If a change materially affects what you pay or what you get, we will email the address on your account before it takes effect. Continuing to use Proselon after that means you accept the change.
15. The fine print
If a court finds part of these terms unenforceable, the rest stays in force, and the unenforceable part applies as far as the law allows. These terms, together with the Privacy Policy, are the whole agreement between you and us about Proselon and replace anything earlier. If we do not enforce a part of them right away, we are not giving it up. You may not transfer this agreement to anyone else, though we may transfer it as part of a sale, merger, or reorganization of our business.
16. Contact
Questions about these terms: hello@proselon.com.