---
title: Verify a signed PDF
description: Check the seal on a signed PDF in your browser. The file is not uploaded.
---

# Verify a signed PDF

Drop a signed PDF into the page; the check runs in your browser and the file is not uploaded. It checks the file still matches what was sealed; it does not say who the signer is in the real world.

## What the check does

Drop a signed PDF into the box. The page reads the file in your browser, recomputes its fingerprint, checks the digital signature over the whole file and the trusted timestamp, and tells you whether anything changed after sealing. The file is not uploaded; nothing leaves your device.

## Reading the result

A valid result means the file is exactly as it was when Docustay sealed it, and names Docustay as the signer. An invalid result means a byte changed or the file was never sealed this way. It does not say whether a signer was who they claimed to be; that is what the certificate page in the file records.

## Questions people ask

**Does this upload my PDF?**

No. The check runs in your browser.

**Is the check the same one a PDF reader does?**

A PDF reader checks the digital signature. This page also recomputes the fingerprint and reads the trusted timestamp, and says it in plain words.

## Keep reading

- [Proof and the signed copy](/product/proof)
- [Legal validity](/trust/legal-validity)
- [Security](/trust/security)
- [How it works](/product)