← Tangent

Privacy Policy

Updated 10 October 2026

Tangent is a shared whiteboard for lessons, operated by DC Math in Singapore ("we", "us"). This policy explains what personal data Tangent collects, why, and what you can do about it. It is written to meet Singapore's Personal Data Protection Act 2012 (PDPA). Questions and requests go to chiadenn@gmail.com.

What we collect

Account details. If you sign in with Google or Apple, we receive your basic account identity: name, email address and profile picture where provided. Signing in does not grant access to Gmail or Drive. If you choose Google Drive import, Tangent separately requests access only to the Drive files you select and temporary files it creates. Guests give a display name and receive a guest identity stored in their browser.

Board content. Boards, page names, handwriting, uploaded images and PDFs, chat messages, raised hands, shared calculator state, Google Meet links, room IDs, who is on each board and who may draw.

Plan details. Whether your account is on the Free or Pro plan and when Pro ends. If you pay for Pro, the payment provider handles your card details; Tangent does not receive or store card numbers.

Video usage. For boards with a built-in call we record how many participant-minutes were used each month, to apply the plan allowance.

Video calls. If you join a board's built-in video call, your audio, video and display name are carried by Daily (daily.co). Tangent does not record calls and does not store call audio or video.

Technical data. Your browser keeps your sign-in session and preferences. Our hosting providers keep short-lived server logs such as IP address, time and the page requested.

Why we use it

To sign you in, show boards to the right people, save and sync writing live, run calls you choose to join, apply plan limits, keep the service secure and answer support requests. We do not sell personal data and do not use it for advertising.

Who can see your content

Everyone on a board can see its writing, attachments, chat, calculators and the display names of other people on it. Anyone with a board's room ID or invite link can join as a viewer, so share them only with the people you intend. The board owner decides who may draw and can remove content.

Safety reports and blocks

You can report a board or its writing from People, a message from Chat, an attachment from Attachments, or a person from People. Reports include your account ID, the reported content, the reason and any details you add, and are visible only to authorised Tangent administrators. We retain reports and moderation decisions while needed to investigate abuse and protect users; contact us to request deletion. Your blocked-users list is private. Blocking hides that person’s writing, files and messages from you and prevents built-in calls together. Owners can block people from all boards they own. Manage or remove blocks in Account → Blocked users. A block cannot recall content already downloaded or copied, and guests can create a new identity after clearing browser data.

Service providers

We use these providers to run Tangent. They process data on our behalf and may store it outside Singapore.

Students and children

Tangent is used by students, some of whom are under 18. A teacher or tutor who invites students is responsible for having the consent of a parent or guardian where the law requires it. Students under 13 should use Tangent only with a parent's or guardian's permission. Guests can take part with a display name only, so a student does not need to give an email address. If you believe a child's data was provided without proper consent, contact us and we will remove it.

How long we keep it

Board content stays until the owner deletes it or the board, or the account is closed. Cleared writing and removed attachment records may stay marked as deleted in the database until permanently purged; ask us if you need that done sooner. Server logs are kept for a short period by our providers. Clearing browser data ends a guest identity.

Your choices

You may ask for a copy of your personal data, ask us to correct it, withdraw consent, or ask us to delete your account and boards, by emailing chiadenn@gmail.com. We will respond within 30 days. You can delete your own account at any time from the account menu in the app (Delete account); this permanently removes your boards, files, writing and sign-in. Owners can also delete individual boards. We keep a count of video minutes per board for billing records, without your name.

Security

Access to board data is restricted in the database to the owner and people who have joined that board, files are private, and connections are encrypted in transit. No online service can promise perfect security. If a data breach is likely to cause significant harm, we will notify affected users and the Personal Data Protection Commission as the PDPA requires.

Google Drive imports

When you choose to import from Google Drive, selected PDFs and images are copied into the shared board. Google Docs, Slides, Word and PowerPoint are imported as PDFs. For Office conversion, Tangent uploads a temporary copy to your Google Drive, converts it using Google, then moves that copy to Drive trash. Original files are not changed. Board members can view imported content. Drive access tokens are held in browser memory, not stored by Tangent. You can revoke access in your Google Account settings.

Google user data

Google account information is used for authentication and identifying your account. It is not sold or used for advertising. Tangent's use and transfer of information received from Google APIs follows the Google API Services User Data Policy, including its Limited Use requirements.

Changes

We will post changes here and update the date above. If a change is significant we will tell signed-in users in the app or by email.

See also the Terms of Use.