Terms of Use

Provider: Marcin Frątczak Labs, ul. Warszawska 40/2A, 40-008 Katowice, Poland, NIP 6252163911

Contact: hello@booksync.link

In force from: September 24, 2026

Both language versions are equally binding.

§ 1. Provider

The services are provided by Marcin Frątczak, trading as Marcin Frątczak Labs, ul. Warszawska 40/2A, 40-008 Katowice, Poland, NIP 6252163911 (“I”). One address handles questions, complaints and reports: hello@booksync.link. It is also the single point of contact for users and authorities under the EU Digital Services Act, in English or Polish.

This document is the regulations required by art. 8 of the Polish Act on Providing Services by Electronic Means. It is available free of charge before you start; you can save or print it.

§ 2. What BookSync is

  • BookSync Manager — a Chrome extension for organising bookmarks: tags, notes, search, cleaning up duplicates and dead links, category suggestions.
  • BookSync Navigator — an extension that replaces the new-tab page: bookmarks, shortcuts and widgets.
  • booksync.link — the information site and newsletter.

Both extensions are free, need no account and keep their data in your browser. A consumer is a person using BookSync outside their business; a sole trader with consumer rights runs a one-person business for which using BookSync is not professional in nature (Polish Civil Code art. 3855) and has the same rights as a consumer.

§ 3. Technical requirements

A current version of Google Chrome (or a browser compatible with Chrome extensions) on a computer. The AI features in Manager need a browser that supports the built-in Gemini Nano model and hardware that meets Google’s requirements; without them everything else works normally. Weather, background photos and link checks need an internet connection.

§ 4. Making and ending the agreement

The agreement to use an extension free of charge is made for an indefinite period when you install it. You can end it at any time by uninstalling the extension, which deletes everything it stored. Your bookmarks stay in Chrome.

Signing up for the newsletter on booksync.link requires confirming your email address; you can unsubscribe with one click in any message.

§ 5. Artificial intelligence

BookSync Manager uses two models that run on your device:

  • Gemini Nano (Google, built into Chrome) — suggests categories and folder names;
  • all-MiniLM-L6-v2 (an open-source model, downloaded once from Hugging Face) — semantic search.

Optionally you can turn on Jev (TypeSafe, a cloud service) — only with your own API key pasted in Settings → AI. Jev picks tags and existing folders; for that, the titles and addresses of the bookmarks being sorted, your tag and folder names and a few example titles go directly from your browser to TypeSafe, under your own agreement with TypeSafe and at your cost. I am not in between and never see your key. Without a key no bookmark data leaves your device.

I do not use your bookmarks to train models. These are minimal-risk systems under the EU AI Act: they do not decide for you, they only propose.

Suggestions can be wrong. Nothing changes in your bookmarks until you approve it — check a proposal before accepting it. I do not guarantee that results are accurate or unique.

§ 6. Complaints — consumers

I am responsible for any non-conformity of an extension that shows up while it is being provided (Polish Consumer Rights Act art. 43k and following). Send the complaint to hello@booksync.link with your name, email address, a description of the problem and a request to bring the extension into conformity. I answer by email within 14 days: accepting the complaint with a date for the fix, refusing a fix that is impossible or disproportionately expensive, or rejecting the complaint as unfounded — always with the reason. Fixes are free.

If a fix is impossible, did not happen, did not help, the problem is serious, or it clearly will not be fixed in reasonable time, you may withdraw from the agreement — uninstall the extension and let me know.

§ 7. Complaints — business users

A business user can complain by email within 30 days of noticing a problem, with their name, email address and a description. I answer within 21 days (30 in complicated cases).

§ 8. Your content, and reporting illegal content

Your bookmarks, tags and notes belong to you and never reach me. BookSync publishes no user content. If you nevertheless come across content in BookSync that you believe is illegal, report it to hello@booksync.link with your reasons, its exact location, your name and email address (not required for reports of child sexual abuse material) and a statement of good faith. I confirm receipt, decide with reasons within 14 days, and any appeal is decided within 14 days by a person, not an automated system.

Feedback you send me is quoted on the site only with your consent.

§ 9. Rules of use

Do not use BookSync for anything illegal, circumvent its safeguards, or distribute modified copies as the original. The BookSync name and logo, interface, graphics, texts and code are protected by copyright, industrial property and unfair competition law; using them beyond these terms requires my permission. Reverse engineering is allowed as far as the law permits.

§ 10. Liability

I provide BookSync with due care and fix faults as soon as I can. Cleanup features move deleted bookmarks to a trash you can restore them from — still, export your bookmarks from Chrome before large changes.

As far as the Polish Civil Code and Consumer Rights Act allow, I am not liable for the results of using the extensions against their purpose, or for interruptions caused by force majeure, changes in Chrome, or outages of third-party services (Open-Meteo, Picsum, Openverse, Hugging Face, Google, TypeSafe). Towards business users, liability for lost profits is excluded. Nothing here limits liability towards consumers beyond what the law permits, or for intentional damage.

§ 11. Changes to the extensions and these terms

I may change the extensions to adapt them to new Chrome versions, to add or improve features, or because the law requires it; a change never costs you anything. If a change materially and negatively affects your access, I announce it in advance in the release notes, and you may end the agreement by uninstalling.

These terms may change because the services, the technology or the law change. The new version is published here with a new date. If you do not accept it, uninstall the extension — until then the previous version applies.

§ 12. Out-of-court dispute resolution

Consumers and sole traders with consumer rights can get help from municipal and district consumer ombudsmen, consumer organisations, the Provincial Inspectorates of Trade Inspection and the Polish Office of Competition and Consumer Protection: uokik.gov.pl. The EU ODR platform closed on 20 July 2025.

§ 13. Personal data

Privacy is described in the policies for the booksync.link site, BookSync Manager and BookSync Navigator.

§ 14. Final provisions

These terms apply from 24 September 2026 and are governed by Polish law; for a consumer that does not remove the protection of the mandatory rules of their country of residence, and disputes with consumers go to the court competent under general rules. Disputes with business users go to the court competent for my place of business. Both language versions of these terms are equally binding.