Privacy Policy

Last updated 18 August 2026

The short version

Ephemeris is a map of your own trips, activities and stays, built from data exports you already own. Your raw export files are read on your own device and are never uploaded. Only the extracted events — where and when, not the original archive — are stored on your account. Nothing is sold, and Ephemeris has no analytics and no advertising of its own. It is not tracker-free, though: the map is drawn by Mapbox, whose library reports map usage back to Mapbox and keeps an anonymous identifier in this browser. That, and everyone else who sees anything, is named below.

Who is responsible

Ephemeris is run by one person as a personal project. For anything in this policy, including any request about your data, the contact address is privacy@ephemeris.app.

What is collected

From signing in

Signing in uses Google. Google passes back your email address, display name and profile picture URL, which are stored so the app can show whose map you are looking at. Your Google password is never seen by this app.

From your imports

When you import an export from Google Timeline, Strava, Garmin or Navionics, the file is opened and parsed in your browser. What gets sent to the server is the extracted record: activities and trips with their times, routes and distances; places you stayed; the areas and days your data covers; and any summits detected from them.

This is location data and, for activities, fitness data. Both are sensitive, which is why the import is built the way it is.

Automatically

A log of your own account actions — when you ran an import or a deletion, and how many records it touched — so the Activity tab can show you what happened. Standard server logs are kept by the hosting providers below.

What is not collected

Your original export files. They are parsed in your browser and never uploaded. No copy of the archive exists on the server, because there is no code path that could put one there.
No analytics or advertising of its own. Ephemeris runs no Google Analytics, no ad network, no profiling, and nothing that follows you to other sites. There is one thing it cannot claim, so it says it plainly instead: the map library it uses, mapbox-gl, sends Mapbox an event each time a map loads, and stores an anonymous identifier in this browser under mapbox.eventData. The version in use offers no supported way to switch that off, so it is disclosed rather than denied.
No connections to Strava, Garmin or Google accounts. Ephemeris takes files you export yourself and has no access to those services.

Why, and on what legal basis

Your data is used for exactly one purpose: showing you your own map. It is processed on the basis of your consent, given when you sign in and when you choose to import a file. Because activity data can reveal information about your health, that consent is the explicit consent required for special-category data under Article 9 of the UK and EU GDPR.

You can withdraw it at any time by deleting your data or your account, on the Data & privacy tab of the Imports panel — the panel that opens from the account chip in the corner of the map. That takes effect immediately. Withdrawing does not affect anything done before you withdrew.

Cookies and browser storage

Ephemeris itself sets only what it needs to work: a session cookie so you stay signed in, a cookie recording which map you are currently viewing — set every time you sign in — and, if you have opened a share link, a cookie holding the links this browser has been given. None of them profile you, and none are advertising cookies.

One thing kept in this browser is not strictly necessary, and it is not Ephemeris that puts it there: the map library stores an anonymous identifier in local storage under mapbox.eventDataand sends it to Mapbox with its usage events. It cannot be turned off from here. Clearing this site’s data removes it, and blocking requests to events.mapbox.com stops the events; the map keeps working either way.

Sharing

Nothing is shared with anyone unless you create a share link yourself. A share link grants read-only access to your map to whoever holds it, so treat one like a password. It also shows them the email address on your account, so they can see whose map they are reading — sending someone a link means sending them your address. (A map embedded in another page deliberately does not show it.)

You can revoke any link at any time from the Sharing tab of the Imports panel, and revocation takes effect on the next request.

Your data is never sold, rented, or used for advertising.

Where it is stored, and who else sees anything

Ephemeris runs on Vercel and stores data in Supabase (a managed PostgreSQL database) hosted in Central EU (Frankfurt). Both act as processors: they hold the data so the app can run, and do not use it for their own purposes. Some processing — request routing and server logs — may happen outside the UK or EEA, under the safeguards in those providers’ own terms.

Two more companies receive something straight from your browser, because the map is drawn there rather than on the server:

Mapbox serves the map itself. Every tile request tells Mapbox which part of the world you are looking at and carries your IP address, and the library also sends it the usage events described above. Your events, places and routes are not sent — they are drawn on top of the map, in your browser.
Googleis asked for a place’s name and address when you click one on the map, on deployments where that lookup is switched on. The request carries only Google’s own identifier for that place and your IP address — not your visit history, not the rest of your map, and nothing that names you.

How long it is kept

For as long as your account exists. There is no automatic expiry, because the whole point of the app is a record that goes back years. When you delete your data or your account it is removed immediately, not queued or archived.

Your rights

Under the UK and EU GDPR you have the right to access your data, correct it, delete it, take it elsewhere, and object to or restrict its use.

Two of these you can exercise yourself, immediately, on the Data & privacy tab of the Imports panel:

Delete my data — removes every event, place, coverage area and summit, and revokes every share link. Your account stays.
Delete my account — the above, plus your account, your profile and your sign-in. Nothing is retained.

For anything else, email privacy@ephemeris.app and you will get a response within one month.

Complaints

If you think your data has been handled improperly, please email first — it is one person and it will be fixed. You also have the right to complain to a regulator: in the UK, the Information Commissioner’s Office (ico.org.uk); in the EU, the data protection authority for the country you live in.

Changes

If this policy changes materially, the date at the top changes and the new version appears here before the change takes effect.