Terms of Service

Last updated: October 28, 2026

These terms cover your use of the Graph Modeler™ website at graphmodeler.com, the Graph Modeler software, and the commercial licenses sold for it. Graph Modeler is published by Jeffrey J. Long ("I", "me"). By downloading or using the software, or by buying a license, you agree to these terms. If you do not agree, do not use them.

The software and its license

The software is licensed, not sold. What you may do with it is set out in the license, and the text of the license on that page is the one that applies. In short, it is free for personal, educational, research and other non-commercial use, and a commercial license is needed for any commercial use. If these terms and the license text disagree, the license text decides.

Graph Modeler is built on the work of others, each under its own license, which are listed on the About tab of the app. Graphviz is not part of Graph Modeler. It is installed separately, under its own license.

The beta

While Graph Modeler is marked beta, it is still being tested. Features may change, files written by one version may not open in an earlier one, and it may contain mistakes. Keep copies of the files you care about.

Commercial licenses

• A commercial license is for the use described in the license. What it covers, such as the number of people and the length of time, is stated at checkout and on your receipt.
• You pay the price shown at checkout. The price does not include any tax that is added at checkout.
• A license belongs to the person or the organization named on the order. You may not give it to someone else, lend it, or sell it, except as I agree in writing (for example, a move to a different person in your organization).
• You may enter the key on your own computers. The app checks it with Polar so that it can show who the license is for. The check never switches off a feature, and if Polar cannot be reached the program carries on. If a license is refunded, the key stops being accepted, and the program can still be used under the free personal and non-commercial terms. What the check sends is described in the Privacy Policy.
• When the app asks and you choose free personal use, you are saying that your use is personal, educational, research or otherwise non-commercial. If it becomes commercial, a commercial license is needed from then on.
• Writing to sales@graphmodeler.com before you buy is welcome, especially when you are not sure whether your use is commercial.

Buying

Purchases are handled by Polar (Polar Software, Inc.), an online reseller that acts as the merchant of record. That means Polar takes your payment, collects and pays any sales tax or VAT, and sends the receipt, and its own terms and privacy policy apply to the payment. Refunds are described on the Refund Policy page.

What you must not do

• Redistribute, sublicense, sell, rent, lease, host or bundle the software, as the license says.
• Use the software to break the law or to harm others.
• Try to get around the license, or use a commercial license for more people than it covers.

Your files

Your projects, data and published files are yours. They stay on your computer, and I do not receive them. The license says nothing about them, and nothing in these terms gives me any right to them. You are responsible for the data you put in, and for having the right to use it.

No warranty

The software is provided "as is", without warranty of any kind, as the license says in full. Graph Modeler is a drawing and modeling tool. It does not check that your model is correct, and you should not rely on it alone where a mistake could harm someone.

Limit of liability

As far as the law allows, I am not liable for lost data, lost profit, loss of use, or any indirect or consequential damage that comes from using the software or the website. As far as the law allows, my liability for any claim about a paid commercial license is limited to the amount you paid for that license. Nothing in these terms limits a liability that the law does not allow to be limited, and nothing takes away rights that the law gives you as a consumer.

Support

I answer questions and reports at support@graphmodeler.com and try to reply within a few working days. Support is offered in good faith. It is not a promise of a fix or of a date.

Changes to these terms

I may change these terms, for example when the product or the way it is sold changes. The date at the top says when they last changed. A change does not apply to a purchase made before it, unless the law requires it.

Ending

You may stop using the software at any time. If you break these terms or the license, the permission to use the software ends, and you must stop using it. The parts of these terms that are meant to last, such as the limit of liability, last.

If someone else takes over

I may assign these terms, and the licenses sold under them, to another person or a company that continues Graph Modeler, for example a company I form to run it. Your license continues on the same terms.

The law that applies

These terms are governed by the laws of the State of Michigan, United States, and the courts in Michigan decide disputes about them, except where the law where you live requires otherwise.

Contact

Write to support@graphmodeler.com about the software, or to sales@graphmodeler.com about licenses.