Last updated: July 17, 2026
ProofStamp is designed so that your data never leaves your computer.
WHAT PROOFSTAMP DOES WITH PAGE CONTENT
ProofStamp captures a screenshot of the region you select, only at the moment you click "Capture region" and drag. The capture is processed entirely in your browser and saved as a PDF or PNG file to your Downloads folder. Captures are held temporarily in Chrome's session memory while the preview is open and are discarded when you close or discard the preview.
WHAT PROOFSTAMP STORES ON YOUR DEVICE
Your settings (export format, time format). Your free-trial usage count. Your license status and license key (locally only), if you purchase.
WHAT PROOFSTAMP SENDS OVER THE NETWORK
One thing only: when you activate a license (and periodically to confirm it is still valid), the extension sends your license key and the product ID to Gumroad's license-verification service (api.gumroad.com). No page content, no captures, no browsing history, and no personal information is ever transmitted.
WHAT PROOFSTAMP DOES NOT DO
No analytics, tracking, or telemetry. No accounts, sign-ins, or cloud storage. No selling or sharing of any data with anyone. No reading of pages in the background the extension only acts when you click it.
PAYMENTS
Payments are processed by Gumroad, Inc. ProofStamp never sees or stores your payment details. Gumroad's privacy policy: https://gumroad.com/privacy
CONTACT
Questions? Email: onceworks.tools@gmail.com