SineGrid Privacy Policy

Last updated: October 2, 2026

SineGrid is a coordinate-plane and worksheet tool provided by Gordon Sine at sinegridmath.com. This policy describes how the app handles your information, including its optional Google Drive connection.

Graphs, worksheets, and imported images

Graph editing, worksheet creation, and image analysis run in your browser. The app does not send imported source images to an external image-analysis service. Graphs and worksheets remain in browser memory until you save or export them. Imported source photos and undo history are not included in graph project files.

Saving to your PC writes or downloads a file to your device. When supported by your browser and authorized by you, SineGrid retains a file handle during the session so Save can update the file you opened or saved. The app does not upload PC files to the website operator.

Optional Google Drive access

You can use the graphing app without connecting Google Drive. If you connect it, Google handles sign-in and consent; SineGrid does not receive your Google password.

SineGrid requests the drive.file permission to create files and access files you select or otherwise authorize for this app. It uses Google's file and folder picker to let you select a project or save location. This permission does not grant unrestricted access to every file in your Drive.

The app accesses your Google display name, email address, and Drive user identifier to show the connected account and distinguish accounts when you switch. It handles the names and identifiers of selected files and folders, and reads or writes the project content needed to carry out your Save, Save As, and Load requests. Save updates the current file; Save As creates a copy in the location you select.

Project data travels directly between your browser and Google over HTTPS. SineGrid's application code does not send Google account information, access tokens, or Drive file contents to a separate SineGrid server. Account information, temporary access tokens, and selected file references are held in browser memory for the current session, not stored in browser local storage by SineGrid.

How information is used and shared

SineGrid uses Google user data only to provide its visible account, file selection, saving, and loading features. It does not sell Google user data, use it for advertising, or use it to train artificial-intelligence models. SineGrid's use and transfer of information received from Google APIs will adhere to the Google API Services User Data Policy, including the Limited Use requirements.

Google processes sign-in and Drive requests under its own privacy policy. The website is hosted through Cloudflare, which may process ordinary connection information, such as IP addresses and request details, to deliver and protect the website under its privacy policy. This is separate from SineGrid's browser-based graph processing.

Browser storage and retention

SineGrid stores a worksheet pane-width preference in browser local storage. You can remove it by clearing this site's browser data. The app does not include advertising or analytics scripts in its application code.

Closing or reloading the app clears its in-memory graph, connection, and file references. Saved PC and Drive files remain in their respective locations until you delete them. Google may retain file versions or deleted items according to your Google account settings and its policies.

Your controls

You can choose PC storage instead of Drive, cancel file selection, switch the connected Google account, or use Disconnect in the Drive window. Disconnect requests revocation of the app's Google access and clears the local connection. You can also review and remove access through your Google Account connections. Removing access does not delete files you already saved.

Delete saved files using your PC's file manager or Google Drive, including their trash or recycle bin where applicable. Switching Google accounts keeps the current graph but clears its previous Drive save destination. School-managed accounts may be subject to additional district restrictions and retention policies.

Classroom use

SineGrid does not require student names, grades, or other student records to create mathematical graphs. Teachers should follow their school's policies when entering or saving classroom information. Google Drive sign-in is optional.

Changes and contact

Updates to this policy will appear on this page with a revised date. For questions about SineGrid or this policy, contact Gordon Sine using the SineGrid user-support email displayed on Google's consent screen when connecting the app.