Privacy Policy
Last updated: October 2026
Your privacy matters. ksefuj is designed so that your invoice data never leaves your browser. Here's exactly what that means.
No Data Collection
ksefuj does not collect, store, or process any personal data. All XML invoice validation happens entirely in your browser using JavaScript. Your files are never uploaded to any server.
No Server Storage
Your XML invoice files never leave your device. There is no backend, no database, and no server-side processing. Once you close the browser tab, the data is gone — we never had access to it in the first place.
Cookies
ksefuj does not use tracking cookies for advertising. The only cookie that may be set is for remembering your language preference. We use Amplitude Analytics which operates without cookies, using anonymized data instead.
Third-Party Services
The site is hosted on Vercel. We use Amplitude Analytics (EU zone — data stays in the European Union) and Vercel Speed Insights. Amplitude captures page views and the interactions we explicitly instrument (e.g. button clicks) to help us understand how the tool is used. Invoice content is never captured. Vercel Speed Insights collects aggregated performance data. This data is used solely for diagnostics and improvement; we do not use it to identify individuals.
When you use the invoice preview, we count how many times a preview is opened and a PDF is downloaded. With each count we record only the page language and the invoice type (such as standard or corrective), never the invoice content or the file name.
No User Accounts
ksefuj does not require registration, login, or any form of user account. You can use all features without providing any personal information.
Open Source & Auditable
ksefuj is fully open source under the Apache 2.0 license. You can inspect, audit, and verify the entire codebase on GitHub at github.com/ksefuj/ksefuj. What you see is what runs in your browser.
Changes to This Policy
If we ever change this privacy policy, the update will be reflected on this page with a new date. Since our core principle is that no data leaves your browser, significant changes are unlikely.
Contact
If you have questions about this privacy policy, contact us at [email protected].