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Terms of service

The rules for using this site and buying Pro, in plain words. By using the site, or buying Pro, you agree to them.

Last updated 1 November 2026

Who we are

KDP Toolkit is a product of DesignOpx (“we”, “us”), a sole trader business based in Sri Lanka. These terms are between you and DesignOpx. You can reach us through the contact page.

Using the free tools

The calculators, templates and guides are free, for your own books and for books you design for clients, as often as you like. The templates you download are yours to use in any project. The cover checker and interior checker give 3 full checks a day for free.

Pro

Pro adds unlimited checks and the Pro tools listed on the pricing page. It is sold as a monthly subscription (“Pro monthly”) or as a one-time purchase (“Lifetime”). Pro is coming soon; these terms apply once it is on sale.

  • License key: after you buy, you receive a license key by email. Entering it on the site turns on Pro in that browser. The key is for you (or one person at your business): please don’t share or publish it. We may turn off a key that is shared widely or used to get around the free limits.
  • Pro monthly renews automatically each month until you cancel. You can cancel at any time from the link in your Paddle receipt email; you keep Pro until the end of the month you have paid for.
  • Lifetime gives Pro for as long as KDP Toolkit offers Pro, including Pro tools added later, for a single payment.
  • Price changes: we may change prices for new purchases. If the price of Pro monthly changes, we will tell existing subscribers by email at least 30 days before their next payment, and they can cancel before then.

Payments

Our order process is conducted by our online reseller Paddle.com. Paddle.com is the Merchant of Record for all our orders. Paddle provides all customer service inquiries and handles returns. When you buy Pro, you also agree to Paddle’s buyer terms. Prices are in US dollars; Paddle adds any sales tax or VAT your country requires at checkout.

Refunds

Your first payment comes with a 14-day money-back guarantee, once per customer; renewals aren’t refunded, but you can cancel any time. See the refund policy for how to ask for a refund and how to cancel.

Approval reports

An approval report shows the results of a check on the date it was made. It isn’t a guarantee from us or from Amazon that KDP will accept the files. Please don’t change a report or present it as something it isn’t.

Your files and content

Your books, covers and files belong to you. The tools run in your browser and don’t upload them, so we never receive or own your content. See the privacy policy.

Accuracy

We build the tools from the specifications Amazon KDP publishes and test them against KDP’s own calculator. Even so, KDP can change its rules at any time, and printing always has small variations. The results are guidance to help you prepare your files, not a promise that KDP will accept them.

Before you publish, always check your files with KDP’s own previewer and, ideally, order a printed proof copy. This includes covers made by the cover fixer: look at the fixed file before you use it. You are responsible for the files you upload to KDP.

No warranty

The site and tools are provided “as is”, without warranties of any kind, including that they will be error-free, always available or fit for a particular purpose. This doesn’t affect your refund rights under the refund policy.

Limitation of liability

To the fullest extent the law allows, we are not liable for any loss or damage that comes from using, or not being able to use, the site or its results. This includes rejected files, printing costs, reprints, lost sales or lost time. If we are found liable, our total liability is limited to what you paid us for Pro in the 12 months before the claim. Nothing in these terms limits any rights you have that cannot be limited by law.

Fair use of the site

Please don’t:

  • try to break, overload or get unauthorised access to the site;
  • get around the free daily limit or Pro by changing the site’s code, or share ways to do so;
  • copy the site and present it as your own service;
  • use the site in a way that breaks the law.

We may stop access, or turn off a license key, for anyone who breaks these rules. If we turn off a key for any other reason, we will refund the unused part.

Not affiliated with Amazon

KDP Toolkit is independent and is not made, endorsed or supported by Amazon or Kindle Direct Publishing. Amazon, Kindle and KDP are trademarks of Amazon.com, Inc. or its affiliates, used here only to describe what the tools are for.

Changes

We may update these terms from time to time. The date at the top shows the latest version. If you keep using the site after a change, the new terms apply. Changes don’t take away anything you have already paid for.

Law

These terms are governed by the laws of Sri Lanka. If you are a consumer, you also keep the protections of the law where you live.

Questions

If anything here is unclear, contact us.