What this site knows about you

The site sets no cookies and uses no third-party analytics. It counts its visits itself and keeps only anonymous daily totals. The only personal data it may keep is what you write yourself in the “Spotted a mistake?” form at the bottom of the guides.

Ulrich Rozier, author of the site (ulrichrozier.com). To reach him: the “Spotted a mistake?” form at the bottom of every guide, leaving an address for the reply, or the contacts listed on ulrichrozier.com.

• No cookies. The site keeps four comfort settings in your browser (local storage, never sent to the server): light or dark theme, the language chosen in the switcher, the guides you have read and your preferred coding agent. You can erase them at any time by clearing this site's data in your browser.
• The site is served from a machine owned by the author, in France. Cloudflare, which carries the traffic and caches the pages, sees your IP address and the pages you request, under its privacy policy.
• Chinese pages load their font (Noto Sans SC) from Google Fonts, so Google receives your IP address, under its privacy policy. French and English pages load nothing from another site.
• The server keeps no visit log. It only records its own technical errors, without your IP address.

Cloudflare caches the site's pages, so the server almost never sees them go by. To know how many people read the site and what they read, each page reports itself to the server when it loads, through a small script written in the page (no third-party service).

• What the script sends when a page opens: the page address without its parameters, the page language, a screen-width bracket (mobile, tablet or desktop) and, if you come from another page, either that page's address when it is on this site, or only the domain name of the site you come from (for example “google.com”). On the “not found” page, it also reports a 404 error.
• When you click a link to another site, the script sends the address of the page you are on and the link's domain name (for example “github.com”), nothing more. It neither holds back nor redirects the link.
• Like any request, these messages carry your IP address (passed on by Cloudflare), its country according to Cloudflare, and your browser description. The server uses them to count a visitor only once per day: it computes a fingerprint from the IP address, the browser description and a number drawn at random each day. The fingerprint stays in memory and disappears at midnight along with that number, which is never written down: it cannot reveal your IP address, recognise you from one day to the next, or follow you on another site.
• Visits: a visit is a series of pages read with the same fingerprint, with no pause longer than 30 minutes. During the visit, the server keeps in memory the time of the first and last page, the page you are on, the number of pages read and whether you followed a link to another site. When the visit ends (30 minutes without a new page, midnight or server shutdown), its figures are added to the day's totals and the visit is forgotten.
• What is kept: daily totals. Page views and visitors, pages read, first page read, the referring site reduced to its domain name, country, screen bracket, page language, hour. For visits: their number, their breakdown by number of pages and by duration, their entry and exit pages, the site they come from. Moves from one page of the site to another (the 300 most frequent of the day, the rest as a single total), clicks to other sites by domain name and by page, and requested addresses that do not exist (404).
• Never written down: your IP address, the fingerprint, your browser description, the exact address of a page on another site you came from, the full address of a link you follow, address parameters, the sequence of pages a person read.
• Robots (search engines, AI assistants) do not run this script. The server separately counts, by robot name, the pages they request from it directly, and keeps nothing else.
• What for: to know the site's audience, its most-read guides, the paths people follow, the links they visit and its broken links, in order to improve it. These totals serve no other purpose, are not cross-referenced with any other data and are shared with no one.
• Legal basis: the author's legitimate interest in measuring his site's audience (Article 6(1)(f) of the GDPR), within the conditions set by the French data protection authority (CNIL) for consent-exempt audience measurement.
• How long: IP address and fingerprint, in memory, until midnight at most; what the server knows about an ongoing visit, also in memory, until the visit ends. The totals, which contain no personal data, are kept with no time limit on the author's machine, in France, and in his backups, also in France.

• Turn on your browser's Global Privacy Control (GPC) or “Do Not Track” (DNT) signal: the script then sends nothing, and the server also ignores any message carrying one of these signals. None of your pages, visits or clicks are counted.
• Without JavaScript, or with a blocker that stops the script, nothing is sent either. The site reads just the same.
• No cookie is needed to opt out, and since nothing kept can identify you, there is nothing about you to access or erase.

• What is kept: the page concerned, its language, your message, the date received and, only if you write it, a way to reply to you (email address or handle).
• What for: to check and fix the site, and to reply if you left a contact. Legal basis: the author's legitimate interest in publishing accurate guides.
• Where: on the author's machine, in France, and in his backups, also in France. The message is also forwarded to his Telegram messenger (Telegram policy), where a copy remains until he deletes it.
• Your IP address is used only in memory, to limit the number of submissions. It is never written down.
• How long: reports are not deleted automatically. You can ask for yours to be erased at any time (see below).
• Nothing is sold, transferred or used to train an AI model.

Cloudflare, Google and Telegram may process data outside the European Union, with the safeguards described in their policies.

You can ask to access, correct or erase what you sent, object to its processing or ask for it to be restricted, through the “Spotted a mistake?” form of the guides (leaving a contact) or the contacts on ulrichrozier.com. You will get an answer within a month.

If the answer does not satisfy you, you can lodge a complaint with the CNIL: cnil.fr.