Last updated: 2026
Nothing is sent to us. Costline has no server and no account system.
All data you enter — ticker symbols, your cost basis, share counts, group names, and settings — is stored only on your device using chrome.storage.local. It never leaves your machine.
To display prices and charts, Costline requests public quote data from Yahoo Finance:
https://query1.finance.yahoo.comhttps://query2.finance.yahoo.comThese requests contain only the ticker symbol. No personal data is transmitted.
When you tap “TradingView ↗”, a new tab opens to TradingView. Your use of that site is governed by their own policies.
We do not collect, sell, or share your data. We do not use analytics or advertising.
Uninstalling the extension removes all stored data from your device.
Questions: [your-email@example.com]