Privacy
Last updated 3 November 2026. Back to the charts
Who's responsible
MChart is a free, non-commercial app run by one private person in Finland, Miika Härmä, who decides what happens to this data. To reach them, email mchart.app@gmail.com, or use Send feedback and include your email address so you can get a reply.
Without an account
Your lists and settings stay in your browser. Prices and charts are cached there too, so the app loads quickly.
With an account
You log in with Google. We store your Google account's id and email address, a username that starts as the part of the address before the @, your lists and your settings. We never get your Google password, and we don't send you mail.
A cookie keeps you logged in. A second cookie lasts up to 10 minutes while you log in. We set no others.
Logs
The server logs each request: the address opened, without any search text, the result and how long it took. Logs don't say who sent a request and hold no IP addresses. Our host keeps them for about 7 days.
Visit counts
We count daily and weekly visitors with a code that resets each week, then keep only the totals, including how many were logged in.
We also count, as daily totals with nothing about who, which pages are opened, which charts are opened, how they're viewed, which features and keys are used, and when a chart fails to load or a search finds nothing. We count which hour of your day you open the app, and whether it's a weekday, as weekly totals only. What you type in search is never sent for this.
To see how many people come back, your browser also remembers the week you first came and how you arrived, such as from a search or a shared link. It sends these when you visit in a new week, and the first time you search, open another chart, change list, save a list or share. It also says if you're on a touch device. They carry no id, and we only add them to totals, so we can't tell who did what.
The server also keeps daily totals of requests and errors for each part of the app, with nothing about who made them.
We use no third-party analytics and sell no data.
Feedback
If you send feedback, we keep your message and its date, with no name or account attached. The server log shows that a message was sent, not what it said. Your email is only stored if you write it in the message. If you email us, we keep the mail in that Gmail inbox for as long as it's useful.
Other services
- The app runs on Fly.io, which handles every request.
- Google handles login, and its Gmail holds mail sent to us.
- Your browser loads company and coin logos from Financial Modeling Prep and CoinCap, which also see your IP address.
Fly.io and Google are US companies, so data can be handled in the United States, under the safeguards in their own terms. Fly stores its logs there.
Why we use it
- Your account, lists and settings: to give you the service you asked for.
- Logs, counts and feedback: our legitimate interest in keeping the app running and safe, and in knowing whether it works for people.
How long we keep it
- Your account and lists: until you ask us to delete them.
- The login cookie: up to a year, or until you log out.
- Logs: about 7 days.
- Totals of requests and errors: 90 days. Visit totals have no end date, as they say nothing about anyone.
- Feedback: for as long as it's useful, unless you ask us to delete it.
Your rights
You can ask to see, correct, delete or take a copy of your data, and object to how it's used. To ask, email mchart.app@gmail.com. Accounts are closed on request for now, by email or through Send feedback. If you think we've got this wrong, you can complain to Finland's Data Protection Ombudsman.