Terms of use
Short version: the tools are free, you owe us nothing, and a green result is a reading of our published rules — not a certificate.
Last updated: 6 September 2026
1. Using the site
Everything here is free to use, including for commercial work, with no account, no registration and no usage limit. Using the site means accepting these terms. The MCP packages published on npm carry their own MIT licence, which governs those packages.
2. What these tools are, and what they are not
Each tool checks your input against a rule list that is published in full on the same page, with an identifier and, wherever a public specification exists, a link to it. That is the whole promise, and it is deliberately a narrow one.
A passing result means your input satisfies the rules listed on that page. It is not a certification, a conformity assessment, a customs ruling, a regulatory approval, or an assurance that any marketplace, authority or trading partner will accept your data. The compliance-oriented tools in particular — product safety, labelling, dangerous goods, declarations of conformity — check the shape and completeness of what you have written. They cannot check whether it is true of your actual product.
Nothing on this site is legal, regulatory, customs, tax or professional advice.
3. Rules reflect specifications at a point in time
Standards and marketplace requirements change, and they change without telling us. Rules here are maintained against their published sources and re-verified periodically, but there will always be a window between a specification changing and this site catching up. Where a decision carries real cost, follow the source link on the rule and read the publisher's own wording. That link is provided precisely so you do not have to take our word for it — and where a source sits behind a login wall, we say where to find it rather than send you to a dead end.
4. Your data and your responsibility
The tools run in your browser and we never receive your files (see the privacy policy). You remain responsible for the data you process, for having the right to process it, and for what you do with the results.
5. No warranty and limitation of liability
The site and the tools are provided “as is”, without warranty of any kind, express or implied, including any warranty of merchantability, fitness for a particular purpose or accuracy. We do not warrant that the site will be available, uninterrupted, or free of errors.
To the fullest extent permitted by law, we are not liable for any loss or damage arising from the use of this site or reliance on its results — including rejected listings, delayed shipments, unpaid invoices, penalties, or lost profit. Nothing here excludes liability that cannot lawfully be excluded.
6. Acceptable use
Use the tools as much as you like, link to any page, and quote them with attribution. What is not permitted is copying or mirroring the site to present it as your own service, or republishing the rule text and explanations as original work. The tools are the free part; the maintained rule set, the verified sources and the test corpus behind them are the part that took the work.
7. Trademarks and independence
Yaktool is an independent project. It is not operated by, affiliated with, endorsed by or certified by GS1, Google, Amazon, Shopify, the European Commission, or any other organisation whose specifications these tools reference. Those names and any others appearing on this site are the trademarks of their respective owners and are used descriptively, to identify the standard being checked.
8. Advertising
This site carries advertising served by Google, which is what keeps it free. What that involves — cookies, personalisation and how to turn personalisation off — is set out in the privacy policy.
9. Changes
These terms may change; the date at the top says when they last did. Continuing to use the site after a change means accepting the revised terms.
10. Contact
Questions about these terms go to our contact page.