Privacy Policy
Last updated: June 2026
Who is responsible for your data
This website (gruzewski.dev) is operated by Mateusz Grużewski, who acts as the data controller for the personal data described below. If you have any question about this policy or want to exercise your rights, you can contact me at privacy@gruzewski.dev.
What data I collect
- Email address — only when you submit it through the newsletter signup form.
- Consent record — to be able to prove that you agreed to receive the newsletter, the date and time of your confirmation and related technical data (such as your IP address) may be stored by my email provider.
- Server logs — like most websites, the hosting provider automatically processes technical data (such as IP address, browser type and the pages requested) in order to operate and secure the site.
Why I process it (legal basis)
- Newsletter — on the basis of your consent (Article 6(1)(a) GDPR), given through a double opt-in confirmation. You can withdraw this consent at any time, which does not affect processing carried out before the withdrawal.
- Operating and securing the site — on the basis of my legitimate interest (Article 6(1)(f) GDPR) in keeping the website available and protected against abuse.
Your email is used solely to send occasional updates about JVM performance, observability and related content. It is never sold or shared for advertising.
Email provider and international transfer
The newsletter is operated through Kit (formerly ConvertKit), which stores and processes your email address on my behalf as a data processor. Kit is based in the United States, so your data is transferred outside the European Economic Area. Such transfers are protected by appropriate safeguards, such as the EU Standard Contractual Clauses and/or the EU–US Data Privacy Framework. For details, see Kit's privacy policy.
Cookies
This site does not use tracking, analytics or advertising cookies. The newsletter form sends only your email address to my server, which forwards it to Kit. Your browser may store a local preference (for example, light or dark theme); this stays on your device and is not sent to me. If this ever changes — for example if I add privacy-friendly analytics — this policy will be updated first.
How long I keep it
Your email address is kept until you unsubscribe or withdraw your consent, after which it is removed from the active mailing list. My provider may retain a minimal suppression record so that your opt-out is respected. Server logs are kept by the hosting provider for a limited period for operational and security purposes.
Your rights
Under the GDPR you have the right to:
- access your data and obtain a copy of it,
- have inaccurate data corrected,
- have your data erased,
- restrict or object to its processing,
- receive your data in a portable format,
- withdraw your consent at any time.
You also have the right to lodge a complaint with a supervisory authority. In Poland this is the President of the Personal Data Protection Office (UODO), uodo.gov.pl.
How to unsubscribe
Every newsletter email contains an unsubscribe link — one click removes you from the list. You can also withdraw your consent or request deletion at any time by emailing me at the address above.
Changes to this policy
I may update this policy from time to time. The “last updated” date at the top always reflects the current version.