NOTE: A text version of the license agreement is available in a file named "license.txt" in the folder where CSS HTML Validator is installed.

License FAQs

Q: Can I purchase a single license and install it on both my home and work computer (or desktop and notebook)?

A: Yes, but only if you are the only user of both computers and only if you do not use both installs at the same time, otherwise you will need more than one license.

Q: Can I transfer or move my license to another computer?

A: Yes. Please see the Transfer or Move License topic.

Q: Can I use a single license for multiple websites/domains?

A: Yes. Licenses are not limited by number of websites/domains.

Q: Can I give or sell my previous license to someone else after upgrading?

A: No. If you upgrade a license, then that license is upgraded and does not become a separate, individual license (another license is not created); only one license still exists.

Q: Can I distribute CSS HTML Validator?

A: Provided no fee is charged, you may distribute the setup program for any trial version in its unmodified form. However, any version that is only for registered users (this includes all versions that you can enter a license key into) MUST NOT be distributed.

IMPORTANT - LICENSE AGREEMENT

This license agreement is for all 2025/v25 versions of CSS HTML Validator, including, but not limited to, all Home and Pro/Professional editions.

UPON BUYING, DOWNLOADING, INSTALLING OR USING ANY VERSION OF THE SOFTWARE, YOU ARE REAFFIRMING THAT YOU ARE BOUND TO THE TERMS OF THIS AGREEMENT.

Unless you have a different license agreement obtained from AI Internet Solutions LLC, installation or use of this software indicates your acceptance of the license and warranty limitation terms contained in this Agreement. If you do not agree to the terms of this Agreement, promptly delete and destroy all copies of the software and do not continue with this installation.

IMPORTANT: The program may periodically and automatically contact a registration server with the registration information entered into the program. This is to verify the license and to limit software piracy. Illegally licensed software may be disabled. This protects our ability to continue to provide support and upgrades. The program should not be used if you do not agree to this.

The software may be used for business, government, personal, and/or educational use in accordance with this license agreement. See the prohibitions at the end of this agreement.

--- HOW TO REGISTER ---

For details on how to register and buy a license, please refer to the help document included with the software, or visit CSS HTML Validator's home page at

https://www.htmlvalidator.com/buy/

--- MULTIPLE EDITIONS of CSS HTML Validator ---

There are multiple editions of CSS HTML Validator which are listed below.

--- EDITION: CSS HTML VALIDATOR ENTERPRISE ---

The Enterprise edition is no longer available in 2025/v25. Most of the extra functionality previously in the Enterprise edition is now available in the Pro edition. Priority support and maintenance (PS&M) is available as an optional add-on for the Home/Pro editions. Please contact us if you have any questions.

--- EDITION: CSS HTML VALIDATOR PRO/PROFESSIONAL (FOR WINDOWS) ---

There are three sub-versions of CSS HTML Validator Pro, each of which is subject to this agreement.

The first sub-version is the unregisterable trial version. The trial version is the only version that is provided without charge; however, the trial version is not free software and cannot be registered by entering a name, key, and PIN number into the software. All rights and licenses to the trial version automatically expire after the trial license period of 30 days or 200 validations (whichever comes first), after which one must pay the appropriate licensing fee to continue using CSS HTML Validator Pro. If you choose not to obtain a license after the trial period, then you must uninstall the software and discontinue any use until a license is obtained. THIS VERSION (THE UNREGISTERABLE TRIAL VERSION) MAY BE DISTRIBUTED. THIS IS THE ONLY SUB-VERSION OF CSS HTML VALIDATOR PROFESSIONAL THAT MAY BE FREELY BE DISTRIBUTED.

The second sub-version is the registerable trial version and is like the first sub-version except that this version can be turned into the third sub-version by entering registration information into the program. To obtain this version, you must first purchase a license to use CSS HTML Validator Pro. You can then download this version from CSS HTML Validator's website by entering your registration information into a web form and/or by following the instructions that are emailed to you when you purchase a license. THIS VERSION MAY NOT BE DISTRIBUTED.

The third sub-version is a registered version. THIS VERSION MAY NOT BE DISTRIBUTED.

The second sub-version (registerable trial version) becomes the third sub-version (registered version) by entering into the second sub-version a registration name, PIN, and key legally obtained and licensed from AI Internet Solutions LLC or a legitimate reseller.

--- EDITION: htmlval, CSS HTML VALIDATOR PRO/PROFESSIONAL (FOR LINUX AND MAC) ---

htmlval is a native command line (console) Linux and Mac (macOS) port of CSS HTML Validator Pro 2025. It is based on the core validation engine in the Windows versions. It does not include all the features in the Windows version, and it does not include a GUI (graphical user interface).

It is licensed for use with a matching valid license for CSS HTML Validator Pro 2025 for Windows. htmlval is also sold separately.

IMPORTANT: A special license is required to use the software for providing a public or private validation service to multiple people or entities. Contact us for more information.

--- EDITION: CSS HTML VALIDATOR HOME (FORMERLY THE STANDARD EDITION) ---

THIS EDITION MAY NOT BE DISTRIBUTED.

The Home edition must be registered by entering registration information (a registration name, PIN, and key legally obtained and licensed from AI Internet Solutions LLC or a legitimate reseller) into the program. To obtain the registration information, you must buy or obtain a valid license to use CSS HTML Validator Home. You can then download this version from CSS HTML Validator's website by entering your registration information into a web form and/or by following the instructions that are emailed to you when you purchase a license.

--- EDITION: CSS HTML VALIDATOR HOME FOR PERSONAL/EDUCATIONAL NON-COMMERCIAL USE ONLY ---

CSS HTML Validator Home for personal, non-commercial use is based on an older version of CSS HTML Validator Home. It is fully functional and there is no day or validation limit, however it is licensed for use only for personal and non-commercial use. It may not be used for commercial, government, or non-personal use.

--- EDITION: CSS HTML VALIDATOR 2025S ---

THIS EDITION MAY NOT BE DISTRIBUTED.

The 2025S edition is based on CSS HTML Validator Home and is targeted for sale and distribution through the Windows Store. This edition does not include upgrade protection and is not eligible for reduced price edition or major version upgrades. However, it is eligible for free minor version updates (like from v25.01 to v25.02).

--- EDITION: CSS HTML VALIDATOR LITE ---

CSS HTML Validator Lite is a free (for commercial, and/or personal use) limited edition of CSS HTML Validator Home. There is no day or validation limit. The Lite edition is limited in features and has limited syntax checking capability. The Lite edition may be limited to use only from within 3rd party products that integrate with CSS HTML Validator.

--- LICENSE TO USE ---

Your license is non-exclusive.

You may not sell, rent, or lease the software to others without the prior express, written permission of AI Internet Solutions LLC.

You may make a reasonable number of copies of any version of the software for backup and archival purposes.

One copy of the trial version of CSS HTML Validator Professional may be used by a single person and on a single computer for evaluation purposes without charge for 30 days or 200 validations, whichever comes first. Reinstalling the same version, or a different version of CSS HTML Validator Professional may or may not restart the trial license.

One license of the registered version of CSS HTML Validator Home or Pro may be:

(a) used by a single person who uses the software personally on one or more computers and is the only user of all the computers, or

(b) installed on a single workstation used non-simultaneously by multiple people.

In the case of (a) above, if one license is installed on more than one computer, then only one installation may be used at a time.

You may access the registered version of CSS HTML Validator Home/Pro remotely over a network if you have obtained enough licenses to cover the total number of workstations that will use the software over the network. For example, if the software will be accessed from five workstations, then five or more licenses (and not three) are required, even if only a maximum of three of those workstations will run the software at any one time. However, if you have more than ten (10) licenses and you have software that allows you to run CSS HTML Validator from a network and that software also manages the number of concurrent users to make sure it is limited to the number of licenses you have, then you only need the number of licenses that are allowed to run concurrently (minimum of ten (10) licenses).

If you are a registered user, then you are entitled to use this product for your own use.

You must not give away your registration key. Doing so will result in an infringement of copyright and your license may be cancelled without a refund.

--- LICENSE TO REDISTRIBUTE ---

You are licensed to make as many copies of the unmodified version of CSS HTML Validator Professional Trial (first sub-version ONLY - the unregisterable trial version) and documentation as you wish, to give exact copies of the unmodified version to anyone, and to distribute the software and documentation in its unmodified form via any means, including electronic distribution and physical media distribution. However, you must try to ensure that you are distributing the latest trial version of this software. YOU MAY NOT DISTRIBUTE ANY REGISTRATION KEYS OR PIN NUMBERS. YOU MAY NOT DISTRIBUTE ANY REGISTERABLE VERSION OF CSS HTML VALIDATOR HOME EDITION OR PRO EDITION.

IMPORTANT: Any redistribution must be in the original, unmodified form. The setup program cannot be distributed to the public by bundling it with or launching it from other software (such as another installer) unless express written permission to do so is acquired from AI Internet Solutions LLC.

--- NO ADDITIONAL LICENSES ---

All rights to the CSS HTML Validator software and documentation not expressly granted under this Agreement are reserved to AI Internet Solutions LLC.

--- USER ACKNOWLEDGEMENTS ---

The licensee acknowledges that (applies to all editions and versions):

(a) title and ownership of the software and patents, trademarks, trade secrets and copyright relating thereto are the exclusive property of AI Internet Solutions LLC and their respective licensors;

(b) licensee shall only acquire the right to use the software in accordance with this agreement; and

(c) licensee shall take all reasonable steps to ensure that all intellectual property which is embodied in the software in licensee's possession remains confidential.

--- PROHIBITIONS ---

The licensee is specifically prohibited from charging, or requesting donations, for any distribution of this software without the prior express written permission of AI Internet Solutions LLC.

The licensee may not (applies to all editions and versions):

(a) translate, decompile, recompile, disassemble or reverse engineer the software or documentation;

(b) copy the software for any reason other than for archival or emergency restart purposes or program error verification;

(c) offer the software for use in a service bureau, or time-sharing environment, except when it is used by the licensee's employees or contractors;

(d) sub-license, rent, or otherwise make the software available outside of the licensee's legal business entities;

(e) assign any rights under this license agreement without the prior written consent of AI Internet Solutions LLC;

(f) use the software to provide free or for money or profit validation or syntax checking services to any entity other than that for which the software is licensed for (for example, using the software to provide validation or syntax checking services to the public or any outside entity is strictly prohibited).

(g) purchase or obtain a single user license that is used to provide validation services for more than one person or computer (for example, purchasing a single license and running it on a server so that more than one person or computer can connect to the server to check documents). If you want to do this, please contact AI Internet Solutions LLC to purchase a license that allows this.

Written permission from AI Internet Solutions LLC is required to override any prohibition.

--- RIGHT TO TERMINATE ---

AI Internet Solutions LLC has the right to terminate any license for any breach of this agreement or in case of piracy or illegal use of the license key. In this case, no payment or refund will be made for a terminated license. At the sole discretion of AI Internet Solutions LLC, a new license may be issued if the reason for the termination has been addressed.

AI Internet Solutions LLC has the right to program its software to periodically contact a server to verify a license, and to automatically deactivate any license that is deemed to be invalid or illegal.

--- LIMITED WARRANTY ---

THE MEDIUM (IF ANY) ON WHICH THE PROGRAM IS FURNISHED IS WARRANTED TO BE FREE OF DEFECTS IN MATERIALS AND WORKMANSHIP UNDER NORMAL USE FOR A PERIOD OF THIRTY (30) DAYS FROM THE DATE OF DELIVERY OF THE SOFTWARE.

THE WARRANTY ABOVE IS IN LIEU OF ALL OTHER WARRANTIES, EITHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

--- DISCLAIMER OF WARRANTY ---

THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTY OF ANY KIND, INCLUDING WITHOUT LIMITATION THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, YEAR 2000 COMPLIANCE, AND NON-INFRINGEMENT. THE ENTIRE RISK WITH RESPECT TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS BORNE BY YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ALONE ASSUME THE ENTIRE COST OF ANY SERVICE AND REPAIR.

SOME STATES DO NOT ALLOW EXCLUSIONS OF AN IMPLIED WARRANTY, SO THIS DISCLAIMER MAY NOT APPLY TO YOU AND YOU MAY HAVE OTHER LEGAL RIGHTS THAT VARY FROM STATE TO STATE OR BY JURISDICTION.

UNDER NO CIRCUMSTANCES AND UNDER NO LEGAL THEORY, TORT, CONTRACT, OR OTHERWISE, SHALL THE PRODUCER OF THIS SOFTWARE, ITS RESPECTIVE LICENSORS, SUPPLIERS, NOR RESELLERS BE LIABLE TO YOU OR ANY OTHER PERSON FOR ANY INDIRECT, SPECIAL, INCIDENTAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LEGAL FEES, DAMAGES FOR USE OR PERFORMANCE OF THE SOFTWARE, NOR FOR DAMAGES FOR LOSS OF PROFITS, GOODWILL, WORK STOPPAGE, COMPUTER FAILURE OR MALFUNCTION, NOR ANY AND ALL OTHER COMMERCIAL DAMAGES OR LOSSES, EVEN IF THE POSSIBILITY OF DAMAGE WAS KNOWN OR SHOULD HAVE BEEN KNOWN. IN NO EVENT WILL THE TOTAL LIABILITY OF AI INTERNET SOLUTIONS LLC, AND ITS RESPECTIVE LICENSORS, IF ANY, EXCEED THE END USER FEE PAID FOR A LICENSE TO USE THE SOFTWARE, EVEN IF THE PRODUCER SHALL HAVE BEEN INFORMED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. THIS LIMITATION OF LIABILITY SHALL NOT APPLY TO LIABILITY FOR DEATH OR PERSONAL INJURY TO THE EXTENT APPLICABLE LAW PROHIBITS SUCH LIMITATION. FURTHERMORE, SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THIS LIMITATION AND EXCLUSION MAY NOT APPLY TO YOU.

--- GOVERNING LAW ---

This agreement shall be governed by the laws of the state of Texas.