Privacy policy · oneby7

oneby7 is a website for learning data structures, algorithms and system design. It is run by one person in India. If you have a question about your data, write to hello@oneby7.com.

Without an account

Pages are served by Cloudflare. Like any web host, Cloudflare sees your IP address and browser details to deliver the page and block attacks. We do not keep these logs.
Code you run on a practice page runs in your browser. It is not sent to us.
Your browser keeps a few things on your device: the theme you picked, which sections you opened, your roadmap ticks, your notes and your code drafts. They stay on your device. Clearing your browser's site data removes them.
We count visits with Cloudflare Web Analytics: which pages are read, roughly from which country, on what kind of device, and when. It sets no cookies and does not follow you to other sites. We do not use advertising trackers.

With an account

When you sign in, we store:

Your email address, to sign you in and to reach you about your account.
Your name and profile picture. With Google sign-in, these come from Google. We ask Google only for your name, email address and profile picture, nothing else.
Your progress: problems you ticked, saved or liked, your streak, and when you opened an article, so that marking it read can wait until you have had time to read it.
Your submissions: the code you submit, its result, and your latest draft for each problem, so it follows you to another device. Only you can see your code.
Your notes: what you write in the notes on problems, lessons and articles. They are private: only you can see them.
What you choose to add to your profile, such as a bio, college, company, city or links. These are optional. Your phone number, if you add it, is never shown to others.
What you post, such as comments and discussion posts. These are public.
Sign-in records: for each device you sign in on, the time, IP address and browser name. You can see them, and sign a device out, in your settings. We use them to keep your account safe.

Cookies

We set two cookies, and only when you sign in. One keeps you signed in. The other protects your account from forged requests. There are no advertising or tracking cookies.

Who else handles your data

We use a few services to run oneby7. Each one gets only what it needs for its job.

Cloudflare hosts the website and passes requests to our server.
Amazon Web Services runs our server, in Mumbai, and keeps our backups.
Supabase runs our database and stores profile pictures, in Mumbai.
Google handles Google sign-in, if you choose it.
An email delivery service sends sign-in codes. It receives your email address and the code.
Kit sends our newsletter, if you subscribe. It receives your email address and handles unsubscribing.

We do not sell your data, and we do not share it for advertising.

How long we keep it

Your account data stays until you delete your account.
Sign-in records are removed 30 days after that sign-in ends.
Email sign-in codes are removed a day after they expire.
Backups of the database are kept for 30 days, then deleted.

Deleting your account

You can delete your account in your settings. When you do, we remove your email address, name, profile picture, bio, profile details and sign-in methods, and sign you out everywhere.

Your posts and comments stay, so discussions still make sense, but they show "Deleted user" instead of your name. Your progress and submissions stay attached to that anonymous record, with nothing left that identifies you. Your notes are deleted. Copies in backups are gone within 30 days.

Your rights

You can ask us for a copy of your data, ask us to correct it, or ask us to delete it. Write to hello@oneby7.com from the address on your account, and we will reply within 30 days.

Age

You must be 18 or older to create an account. Anyone can read the site and run code without one.

Changes

If we change this policy, we will update the date at the top. If a change affects how we use data you already gave us, we will tell you on the site or by email first.