Pixel bytes still match
The strongest result. The original file still matches the signature created when ProStamp captured the media.
Verification
Verify a ProStamp proof photo.
Check whether a capture still matches its signed evidence trail, from original files to recompressed copies.
Web verifier in progress
Full verification is available in the iOS app today.
Web upload is coming soon.
Browser verification will start with original ProStamp JPEG files and expand carefully as it reaches parity with the app.
- Best file
- Original JPEG from AirDrop, email attachment, ZIP archive, or ProStamp bundle.
- Use caution
- Chat apps often recompress images, which can reduce verification to metadata-only.
Capture details still match
The timestamp, location, and signed metadata are intact, but the image bytes were likely recompressed after sharing.
Signature cannot be trusted
The file may have been changed outside ProStamp, stripped of verification metadata, or paired with the wrong code.
How it works
Verification follows the evidence, not just the screenshot.
Every ProStamp capture can carry signed information about when and where it was taken. Newer captures can also bind the original image bytes, which makes the original file meaningfully stronger than a screenshot or chat-compressed copy.
- Capture in ProStamp The app records the visual watermark, location context, and verification metadata at capture time.
- Keep the original Share by AirDrop, email attachment, ZIP archive, or ProStamp bundle when evidence-grade verification matters.
- Verify before relying on it Use the ProStamp iOS app now, and this web page once browser verification is released.
What to send for the best result
- Original ProStamp JPEG
- ProStamp verifiable bundle ZIP
- Email attachment, not inline preview
- AirDrop transfer between Apple devices
What can weaken verification
- Messaging app compression
- Screenshot of a photo
- Edited or resized exports
- Missing metadata or wrong verification code