SinLines Privacy Policy

What the law says, simply: an app must tell you clearly what it collects and why, use your data only for that purpose with your consent (or for a few lawful uses), keep it safe, delete it when it is no longer needed and tell you and the Data Protection Board of India about any data breach. You have the right to information about your data, to correct and erase it, to have your complaints handled and to name someone to act for you if you can't. Children are people under 18: their data needs a parent's verifiable consent, and they must not be tracked or targeted with ads. The Rules 2025 set out how this works in practice; most of their duties apply from May 2027.

How SinLines follows it:

• This policy is our notice, in plain language, with each thing we keep and why.
• We ask you to accept it before you use SinLines, and you can withdraw optional consents (marketing, analytics) at any time in Settings > Legal.
• We keep only what SinLines needs and delete accounts 7 days after you ask.
• Your account data is stored in Japan (Supabase's Tokyo region) and our encrypted backups in the United States. The Act allows this; if the Government of India ever restricts a country, we will follow that.
• Your data is protected as described in "How your data is protected".
• You can see, download, correct and delete your data in the app, or write to sinlines.read@gmail.com. You can also name a person to act for you by writing to us.
• Readers under 18 get teen mode: no tracking for analytics, no marketing and no targeted ads (SinLines has no ads at all). We ask for a parent's consent and are building a fuller way to verify it before the Rules require it.
• If a breach puts your data at risk, we will tell you and the Data Protection Board as the law requires.
• If you are unhappy with our answer, you can complain to the Data Protection Board of India.

What the law says, simply: an app needs a lawful reason to use your data, must collect only what it needs and must keep it safe. You have the right to access, correct, delete, restrict and take away (port) your data, to object to some uses and to withdraw consent at any time. Children below their country's age of digital consent (between 13 and 16; 13 in the UK) need a parent's consent where an app relies on consent.

How SinLines follows it:

• Our reasons: running your account, sync and streaks is needed to provide SinLines to you (contract). sinLes counts and security logs rely on our legitimate interest in improving and protecting SinLines, and you can turn analytics off. Marketing is only with your consent.
• Your rights: download your data (Settings > Legal), correct it, delete your account, turn optional uses off, or write to sinlines.read@gmail.com for anything else, including restriction and objection.
• Transfers: your data is stored in Supabase's Tokyo region, in Japan, and our encrypted backups with GitHub in the United States. Where data leaves the EU or UK, our providers use the safeguards the law requires, such as Standard Contractual Clauses.
• Children: under-18s get teen mode, and accounts for children under the age your country sets need a parent's consent.
• Complaints: you can complain to the data protection authority in your country, or the ICO in the UK.

What the law says, simply: in California you have the right to know what personal information an app collects, to delete and correct it, to opt out of it being sold or shared for advertising, and not to be treated differently for using these rights. Other states have similar laws. COPPA protects children under 13: an app must get a parent's consent before collecting their personal information.

How SinLines follows it:

• We collect only what is listed in this policy, for the reasons given.
• We do not sell or share your personal information, and we use none of it for advertising, so there is nothing to opt out of.
• You can see, download, correct and delete your data in the app or by writing to sinlines.read@gmail.com, and using these rights never changes how SinLines works for you.
• SinLines is not aimed at children under 13; an account for a child under 13 needs a parent's consent. A parent who believes their child under 13 made an account can write to us and we will delete it.

What the law says, simply: many countries have privacy laws that work much like the ones above: tell people what you collect, use it fairly, keep it safe and let them see and delete it.

How SinLines follows it: we give everyone, wherever they live, the same protections and rights described in this policy. If your local law gives you more, write to sinlines.read@gmail.com and we will honour it.

The rules for using SinLines: your account, SinLines Premium and subscriptions (they renew automatically until you cancel them through the App Store or Google Play), what you may and may not do, who owns what (most of our books are in the public domain) and the limits of our responsibility. Read the full Terms and conditions.

On your phone: books and PDFs you add (seen only by the account that added them), your place in them, a copy of My words for each account, your settings, your reminders, the sinLes cards you've seen, your reading days (a copy), copies of catalog books you've opened (the cache, so books open faster and work offline) and the random id of this device. Your login is kept in the phone's secure storage (the Keychain on iPhone, the Keystore on Android). In a web browser it is kept in the browser's own storage.

On our server: your account, your place in catalog books, your reading days, your saved lines, My words, sinLes counts and feedback (see "What SinLines keeps").

To clear things on your phone:

• Remove a book you added: Browse > My uploads, then press and hold the book.
• Remove a looked-up word: Menu > My words, then tap × next to it.
• Sign out: Menu > Log out. This removes your login and your reading days from the phone; they stay safe in your account.
• Clear the cache (the copies of catalog books): on Android, Settings > Apps > SinLines > Storage > Clear cache. iPhone has no clear-cache button for single apps; it clears the cache by itself when it runs low on space.
• Remove everything SinLines keeps on the phone: delete the app. On Android you can also use Settings > Apps > SinLines > Storage > Clear storage.

Clearing your phone doesn't delete your account. To delete what is on our server, use Profile > Delete account.

• Marketing is off unless you turn it on (Settings > Legal > Marketing). If you turn it on, we may tell you about new books and features inside the app or with a notification. Turn it off at any time.
• Referrals: you can share SinLines with friends by sending a link from your phone's share menu. You choose who gets it. We never upload, read or keep your contacts or address book.
• We never sell your data and SinLines shows no ads from other companies.
• Teens (under 18): no marketing and no referral rewards.

• On the way: everything the app sends to or receives from our server travels over HTTPS (TLS), so others on the network can't read it.
• On our server: our provider, Supabase, encrypts the stored data (encryption at rest).
• Passwords: handled by Supabase's login service and stored only in a hashed form. We can't see your password.
• Only you see your data: our database checks every request (row-level security), so a signed-in reader can only read and change their own account's data, and guests can't read any of it.
• Premium books: only our server hands them out, after checking your premium, your device and the daily limit, as a link that works for 60 seconds.
• On your phone: your login is kept in the phone's secure storage (the Keychain on iPhone, the Keystore on Android).
• Backups: encrypted (AES-256) before they are stored, and kept for 90 days.
• Keys: the master key to our database is never put in the app. It is kept only by us.

No system is perfectly secure. If something goes wrong and your data is at risk, we will tell you and the authorities as the law requires.