Yes. The Windows app is in the Microsoft Store and available as a direct download, the Chrome extension is live in the Chrome Web Store, and the checker is free to use. Create an account and connect it in a minute.

What's free and what's Pro?

Spelling and grammar checking is free, in every app, with a plain reason for each fix. Pro is $20 a month and adds one-tap rewrites and natural-tone suggestions, with no daily cap on everyday use. Month to month; you will never discover a price change on a renewal notice.

No. The checker is free and stays free, with honest daily limits rather than a nag screen. You only pay for Pro if you want the rewrites and the natural-tone help.

Is Owlproof a Grammarly alternative?

Yes, for the people who want the original job done. In late 2025 Grammarly rebranded and repositioned around AI productivity tools. Owlproof stays a spelling and grammar checker: it checks as you type, explains each fix in plain English, keeps your voice, and costs $20 a month month to month, with a free tier that stays free.

Do I need an account?

Yes. A free account is what connects the app and extension to you. Sign up with an email and password or with Google. We don't sell it or use it for anything but running your checks.

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Terms of Use

Effective September 13, 2026

These Terms of Use (“Terms”) are an agreement between you and Mako Logics LLC (“Owlproof,” “we,” “us”) covering the Owlproof website, browser extension, and Windows app (together, the “Service”). By creating an account or using the Service, you agree to these Terms and to our Privacy Policy. If you do not agree, do not use the Service. Owlproof is a United States product intended for users in the United States.

1. Who can use Owlproof

You must be at least 13 years old to use the Service, and old enough to form a binding contract where you live. If you use Owlproof on behalf of a business, you confirm you are authorized to accept these Terms for it.

2. What the Service does

Owlproof checks your spelling and grammar and, on the Pro plan, offers rewrites and tone suggestions. The corrections and rewrites are generated by AI and are suggestions, not guarantees. They can be wrong, incomplete, or not right for your context, and they are not legal, medical, financial, or other professional advice. You are responsible for reviewing anything before you rely on it or send it.

3. Your account

A free account is required to use Owlproof. Keep your password and device keys confidential; you are responsible for activity under your account. Tell us promptly at support@owlproof.app if you think your account has been used without your permission. One person or business per account; do not share credentials or device keys to give the Service to people who have not agreed to these Terms.

4. Free plan, Pro plan, and changes to the Service

Owlproof offers a free plan and a paid “Pro” plan. The free plan includes spelling and grammar checking subject to reasonable daily limits we set to control abuse and cost. Pro adds rewrites, tone suggestions, and higher limits with no daily cap on everyday use, all subject to the fair-use terms in Section 6.

We reserve the right to change, limit, suspend, or remove the free plan (and to change, add, limit, suspend, or discontinue any other part of the Service, including features and limits) at any time, with or without notice. The free plan is offered at our discretion and is not guaranteed to remain available or free. Where a change is material and we reasonably can, we will try to give you advance notice. Your continued use after a change means you accept it.

5. Billing for Pro

Owlproof Pro is $20 per month (plus any applicable tax). Payment is processed by Stripe. When you subscribe, you authorize us to charge your payment method the then-current price each month until you cancel. The subscription renews automatically every month.

Cancel anytime. Cancel in your account (Manage billing) or by emailing support@owlproof.app. Cancellation stops the next renewal; you keep Pro until the end of the period you already paid for.
No long-term contract. Pro is month to month. We do not sell annual contracts and do not lock you in.
Refunds. Charges are generally non-refundable and we do not prorate partial months, except where required by law. If something goes wrong, email us and we will be reasonable.
Price changes. If we change the Pro price, we will give you notice before it applies to your next renewal, and you can cancel if you do not want to continue.
Failed payments. If a payment fails, we may retry it and may downgrade your account to the free plan until it is resolved.

6. Acceptable use

You agree not to:

use the Service to break the law or infringe anyone’s rights;
get around usage limits, rate limits, or the account or payment system, or run the Service through automated means beyond normal personal or business use;
resell, sublicense, or provide the Service to others as if it were your own;
reverse engineer, decompile, or try to extract our source code or models, except where the law says you may;
submit text you have no right to submit, or use the Service to process other people’s personal information unlawfully;
interfere with, overload, or attempt to gain unauthorized access to the Service or its infrastructure.

Fair use. Even where a plan is described as having “no daily cap” or similar, the Service is meant for normal individual or business writing, not for automated, scripted, bulk, or resale use. We apply fair-use limits and safeguards to protect the Service and control cost, and we may throttle, cap, suspend, or terminate any account whose usage is automated, abusive, fraudulent, or abnormally high, or that would otherwise impose excessive cost on us. Doing so is not a breach of these Terms or of any description of the Service, and “no daily cap” or similar phrases never mean a right to unlimited, automated, or abusive consumption.

7. Your text and content

The text you check stays yours. To provide the Service, you grant us a limited license to process that text (including sending it to the AI providers described in our Privacy Policy) solely to generate and return your corrections and rewrites. We do not store your text, sell it, or use it to train our own models. You are responsible for the text you submit and for how you use the results.

8. Our intellectual property

Owlproof, its name, logo, software, and website are owned by Mako Logics LLC and protected by law. These Terms do not give you any ownership of them. We grant you a personal, revocable, non-transferable right to use the Service while you comply with these Terms.

9. Disclaimers

The Service is provided “as is” and “as available,” without warranties of any kind, whether express or implied, including any implied warranties of merchantability, fitness for a particular purpose, and non-infringement. We do not warrant that the Service will be uninterrupted, error-free, or that its suggestions will be accurate or suitable for your needs.

10. Limitation of liability

To the fullest extent permitted by law, Mako Logics LLC will not be liable for any indirect, incidental, special, consequential, or punitive damages, or for any lost profits, data, or goodwill, arising from your use of the Service. Our total liability for any claim relating to the Service will not exceed the greater of the amount you paid us for the Service in the twelve months before the claim, or fifty US dollars.

11. Indemnification

You agree to defend and hold Mako Logics LLC harmless from claims and costs arising out of your misuse of the Service, your violation of these Terms, or your violation of the law or anyone’s rights.

12. Suspension and termination

You can stop using the Service and delete your account at any time. We may suspend or terminate your access if you breach these Terms, misuse the Service, or create risk or legal exposure for us or others. If we terminate your account without cause and you were on Pro, we will refund any unused, prepaid portion. Sections that by their nature should survive (such as intellectual property, disclaimers, limitation of liability, and indemnification) will survive termination.

13. Governing law

These Terms are governed by the laws of the State of Texas and applicable United States federal law, without regard to conflict-of-law rules. You agree that the state and federal courts located in Texas are the proper venue for any dispute that is not otherwise resolved, and you consent to their jurisdiction.

14. Changes to these Terms

We may update these Terms from time to time. When we do, we will change the date above and, for material changes, tell you plainly. Your continued use of the Service after a change means you accept the updated Terms.

15. Contact

Questions about these Terms? Email support@owlproof.app.