Privacy & Data

ETHERSIM · ethersim.ai — self-hosted, open source · last updated 26 Jun 2026

The short version: ETHERSIM runs entirely on our own server. We keep a small amount of privacy-respecting analytics to understand whether the project is useful and to keep the server secure. There are no third-party trackers, no cookies, no advertising, and we never sell or share your data. Nothing about the simulations you run, the images you export, or what you do inside the app is sent anywhere — the app is fully client-side.

What we collect

Only what a standard web server sees when your browser requests a page, recorded server-side (nothing is embedded in the page to watch you):

Requests — date/time, the page or file requested, and the response status.
Referrer — the site you arrived from (e.g. a GitHub link or a direct visit), so we can tell how people find the project.
Browser/device type — from the User-Agent your browser sends (e.g. "Chrome on macOS"), and whether the request is a bot.
Approximate country — derived from your IP address using a database stored locally on our server. No external geolocation service is contacted.

How we handle IP addresses

Your IP address is personal data, so we minimise it:

In analytics, the IP is never stored — we keep only a one-way salted hash, which lets us count unique visitors without retaining the address itself.
Full IP addresses are kept only in security logs (to detect and block scanning, brute-force, and abuse) and are deleted after 90 days.

Why we collect it

To understand traffic and where it comes from — is anyone finding this useful, and how?
For historical and planning purposes (aggregate trends over time).
To detect, investigate, and prevent attacks on the server.

We cannot and do not track you across other websites, identify you personally, or know why you visited.

When you favourite a system (❤)

If you tap the ❤ on a system, your browser sends a single anonymous request so we can count how many people liked it. It carries no account or identity; duplicate likes are collapsed using the same one-way salted IP hash described above, so one person isn't counted twice. Un-favouriting is local only. Your ❤s and other preferences live in your browser's localStorage, on your device — they are never uploaded.

What we do NOT do

No Google Analytics or any third-party analytics.
No cookies or browser fingerprinting.
No advertising, no data brokers, no selling or sharing of data.
No tracking of your in-app activity, exports, or simulation content — the only thing you can send is an anonymous ❤ count, and only if you tap it.

Retention

Aggregated, non-identifying analytics may be kept indefinitely for historical trends. Raw security logs (which may contain full IPs) are retained for at most 90 days.

Contact

Questions or requests about your data: open an issue at github.com/macncrash/realethersim.