PDF Signature Checker
Check whether a PDF contains a digital signature field, and see what plain-text signing details (signer name, reason, date) are embedded in it.
This tool detects whether a signature field is present and reads its plain-text metadata. It does not cryptographically verify the signature, check the signer's certificate, or confirm the document hasn't been altered since signing - that requires a full PKCS#7/X.509 validation stack beyond what a lightweight browser tool can safely and correctly provide. Use Adobe Acrobat or a dedicated PDF signing platform for real signature validation.
Recommended Settings
Pro Tips
- •This checks for the presence of a signature field and reads whatever optional plain-text details (name, reason, date) the signer included - many signatures include none of these fields at all
- •A document showing a signature here has been electronically or digitally signed at some point - but this doesn't confirm the signature is currently valid or that the document wasn't modified afterward
- •For real cryptographic verification (checking the signature is mathematically valid and the certificate is trusted), open the PDF in Adobe Acrobat Reader, which will show a green checkmark or a specific validation error
- •All processing happens by reading the raw file locally - your PDF is never uploaded anywhere
Most Popular
Most users check a contract or official document to confirm it was signed and see who signed it and when
When to Use This Tool
Quickly confirm whether a received PDF contains a digital signature at all.
Check the signer, reason, and date recorded in a signed document before filing it.
Catch a draft contract that's missing an expected signature before sending it further.
See how digital signature information is embedded within a PDF's internal structure.
How It Works
Read the PDF's raw bytes directly in your browser without uploading the file anywhere
Search the file's internal structure for signature dictionary markers (/Type /Sig and /ByteRange)
Extract any available plain-text fields near each signature, like the signer's name, reason, and signing time
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side raw PDF structure parsing for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Does this verify the signature is authentic and valid?
No, this tool only detects that a signature field exists and reads its plain-text metadata. Full cryptographic verification - checking the signature mathematically matches the document and that the signer's certificate is trusted - requires a dedicated PDF viewer like Adobe Acrobat Reader.
Can this tell me if the document was altered after signing?
No, detecting tampering after signing requires verifying the cryptographic signature against the document's current byte content, which this tool doesn't perform.
Why is some signature information missing?
Fields like signer name, reason, and location are optional in the PDF signature standard - many signing tools don't include all of them, so a blank field just means that information wasn't recorded, not that something is wrong.
Is my file uploaded anywhere?
No. The PDF is read and parsed entirely in your browser using its raw file bytes - it's never uploaded to any server.
What does 'ByteRange' mean?
It's a required part of every PDF digital signature that specifies exactly which bytes of the file were included in the signature calculation - its presence is one of the clearest signs of an actual embedded signature.