free upgrade incentive FREE UPGRADE: Buy 2019/v19 now and automatically receive a FREE upgrade to 2020/v20 when available.

more information Version 19.03 is now available.
  • Licenses never expire and are NOT limited by number of websites or domains.
  • Licenses start at only $69. This is not a subscription. It's a one-time cost (although major upgrades may incur an upgrade fee).
  • Your purchase is backed by our 30-day money back guarantee!
  • You may use one license on up to two computers if you are the only user of both computers.

More Information

CSS HTML Validator Detailed Buying Information

Upon registering, you will receive a registration name, PIN, and key by email. After you receive your registration information, you can then download a registerable version and convert it into the full version by entering your registration information.

No software or printed documentation is physically sent to you because the latest version (with electronic documentation) is always available for download on the Internet. However, you can download the setup program and store it on a disc or other backup location for safekeeping.

When buying two or more licenses you may qualify for a volume discount if you buy them at one time with a single order. If you are buying the standard edition, then you may also qualify for another discount if you are a student, non-profit organization, or educational institution and the license will NOT be used for business or government use.

Price per License (in USD)
Quantity Enterprise Professional Standard
1 $349 $129 $69
2-9 $299 $109 $69
10-19 $199 $89 $59
20-99 $199 $79 $49
100+ Contact us Contact us Contact us

Payment options include credit card, PayPal, electronic check (checking account), or wire transfer. Other options may be available depending on where you live.

NOTE: The standard edition includes 60 days of FREE upgrades. The professional edition include 180 days of FREE major upgrades. The enterprise edition includes one year of priority support and maintenance (PS&M). There are other differences as well.

Discounts for students, non-profit organizations, and educational institutions are also available.

Compare Editions  Gov't Information  Site Licenses  Buy Upgrade  Upgrade Policy  Classroom Use

After placing an order, please wait for download and registration information to be emailed to you. This will allow you to download a registerable version and register it.

Upgrade an Existing License

If you're already a registered CSS HTML Validator user and your name and email is in our registered user database, then you can buy an upgrade to the latest version, upgrade your edition, or add priority support and maintenance (PS&M) to your license.

The upgrade page will show you what upgrades are available to you. You will need the email address that is in our database (this is usually the one that you registered with).

Buy Upgrade

Purchase Orders

Contact us to buy using a purchase order (minimum $1000). There may be an additional processing fee. Be sure to indicate the quantity and edition desired. Alternatively, a reseller listed below may be able to process a purchase order with a reduced minimum requirement.

Problem with Your Order? We're Here to Help!

For buying questions, problems encountered while trying to buy, or any other question, please contact us. You may also call us in the US at 940-295-4720. However, it is recommended that you contact us electronically for any questions that you may have.

Government Information

Some government agencies, including US government agencies, have purchased CSS HTML Validator licenses and are clients of ours. US Government agencies may be interested in CSS HTML Validator's Section 508 VPAT (PDF). Please contact us if you have any questions about government purchasing and licensing.

AI Internet Solutions LLC is classified by the US gov't as a small business.

Optional Priority Support and Maintenance (PS&M)

Optional priority support and maintenance (PS&M) (for one and two year periods) is available. This includes priority support for technical support questions as well as guaranteed free major upgrades during the priority support and maintenance period.

To add PS&M to your order, simply choose the appropriate option on the order page to add PS&M for the desired period (one or two years). The below prices are valid only when buying new licenses or when buying version or edition upgrades for existing licenses and are in addition to the new license or upgrade price.

NOTE: New orders for (and upgrades to) the enterprise edition include one year of PS&M at no additional cost.

PS&M Pricing for New Licenses and When Upgrading (price per license in USD)
Time Period Enterprise Professional Standard
One Year Included ($0) $79 $79
Two Years $199 $139 $139


Our primary reseller that processes payments for most purchases is BlueSnap. Below is additional address, contact, and tax information for BlueSnap:

BlueSnap, Inc. 800 South Street, Suite 640 Waltham, MA 02453 USA Voice: 1-866-312-7733 Fax: 1-858-777-5553 Tax ID: 45-0479415 Vat ID: EU826002156

30-Day Money Back Guarantee

AI Internet Solutions offers a 30-day money back guarantee. If you are not completely satisfied with CSS HTML Validator, then we will gladly give you a refund if you tell us within 30 days of your purchase.

Other Resellers

You may also be able to buy CSS HTML Validator from one of the below software resellers: