Verify a Signed PDF
Check whether a PDF signed with Formesign is genuine and unchanged, and understand each result.
Reviewed 2026-10-30 · Formesign guides
Quick Answer
How do I check that a signed PDF hasn't been changed?
Go to formesign.com/esign/verify.html and drop the PDF on the page. Valid document. File contents verified means the file matches the original byte for byte. This document has been modified after signing means it doesn't. The result also lists the envelope ID, when it was generated, and who signed.
Anyone with the file can check it. They don't need a Formesign account.
Open the verify page
Go to formesign.com/esign/verify.html.
Add the PDF
Drag the original file onto Browse or drag a file here. The file's contents are sent to Formesign for the check, so only use a document you're allowed to share.
Read the result
Compare the details with the request you expected: the document, envelope ID, generation time, signers, and when they signed. Times are in UTC.
What the results mean
| Result | What it tells you |
|---|---|
| Valid document. File contents verified. | The file matches the original, byte for byte |
| Valid document ID. (issued before content verification) | The envelope ID is genuine, but this older document's contents couldn't be compared |
| This document has been modified after signing | The file doesn't match the original |
| Not recognized, or a failure | Formesign couldn't check it. It may not be a Formesign document, or not a PDF |
Innocent changes fail too
Printing to PDF, adding a page, or re-saving in another app changes the file, even if it looks the same. Ask for the original before assuming tampering.
What verification doesn't tell you
Verification shows that the file is unchanged, and who signed it according to Formesign's record. It doesn't decide whether the wording is legally sufficient, or whether someone had the authority to sign. Keep the original with your other records.