PDF Signature Checker Online — Free
Runs 100% in your browser — your files never leave your device.
Contracts and invoices often arrive as signed PDFs, and you may need to confirm the signature before trusting them. Drop a PDF here to list every embedded signature with its certificate chain, validity dates, signer name, and location. Parsing happens entirely in your browser — the document is never uploaded.
How it works
- 1
Drop a PDF
Drag and drop the document or click to browse.
- 2
Review the signatures
Each signature shows its certificate, validity period, and signer metadata.
- 3
Check authenticity
Verification flags summarize integrity, authenticity, and expiry.
About this tool
What the check reveals
The tool inspects a PDF for digital signatures and reports whether signatures exist, whether the signed content has been modified after signing, and which certificate signed it. It answers the integrity question: is this the document that was signed, or a version edited since?
The trust chain, honestly
A valid cryptographic signature proves the document is unchanged since signing — by whoever held that signing key. Whether that key belongs to a person or organization you trust is a separate question involving certificate authorities; the tool shows what it can see locally so you can judge.
Runs on your device
The PDF is parsed entirely in your browser — contracts and signed documents are exactly the files that should not be uploaded to random services, so the check happens locally and the document never leaves your device.
Frequently asked questions
What is the difference between a signed and an certified PDF?
A signed document carries a cryptographic signature over its content; certification extends that to cover permitted later changes. The tool reports what it finds rather than assuming.
Why does the signature show as invalid?
The document changed after signing — even metadata edits can break the hash. An invalid signature is information: either someone modified the file, or the signing process had a problem.
Does this check handwritten or scanned signatures?
No — a scanned signature image is a picture, not cryptographic data. The tool verifies digital signatures, which are mathematically attached to the content.