What happens to your birth data

When you press Calculate, your browser sends the birth date, birth time, whether the time is known, the place’s latitude and longitude, its time-zone name and your house and zodiac choices to the server (POST /api/chart). The server computes the chart and the rarity figures and sends the result back. The request body is not added to the page address.

While you type a place, the text you typed is sent to GET /api/cities as part of the address (for example ?q=lisb) to find matching cities. The place name itself is not part of the chart request.

A chart link holds the birth details, place name and options in the part of the address after the #. Browsers do not send that part to any server, so loading a shared link does not send the birth data in the page request. The chart is then computed with the same request as above. Anyone who has the link can see what is in it, so share it with care.

Nothing about you in a database. The pages read published reference data and simulation results from a database; the chart and place routes never write to it. The only thing written about a visit is the short-lived rate-limit counter described below. There are no accounts, no saved charts and no cookies set by the site.

Rate limiting: to keep the calculator available to everyone, the chart, place-search and rarity routes count requests per visitor. The counter is kept in Redis under a key made from your IP address and a one-way hash of your IP address, browser name and language, and it expires after 60 seconds. It holds a number, not birth data, place text or anything you entered. If you send too many requests in a minute the server answers with a “too many requests” message (HTTP 429) and asks you to wait.

Server logs: the application writes a log line only when something fails, and it records only the route and the kind of error, never the request, the birth data or the place text. The server or hosting provider in front of it may also keep ordinary access logs (time, address requested, status, IP address and browser name). Those logs can include the place text from /api/cities?q=. No retention period is published for them yet.

The site uses the browser’s local storage, on your device only, for three conveniences. Clearing site data removes them, and the site works without them.

• The last chart you entered (date, time, place and options, in the same form as the share link), so the form is ready next time.
• Which lessons you have opened, so the course can show where you left off.
• Which guided tours you have already seen.

No analytics, advertising or tracking scripts are used, and the one-way hash above is computed on the server, not by a script in your browser. Fonts are bundled with the site at build time and served from the same address, so no request goes to a font provider. Links to other sites (the Swiss Ephemeris, GeoNames, reference sources) only leave the site when you click them.

Questions, corrections and privacy requests: [email protected].

How the chart and the figures are computed is on the about page.