Verify a signed PDF
Drop any PDF you signed with AttachKit. We'll read the embedded proof, re-check the timestamp, and show you exactly what's verifiable — whether you signed with the standard audit trail or a passkey (Max).
For auditors: the proof block carries the HMAC timestamp and (on Max) every WebAuthn field, all inspectable.
Verification is fully client-side — your PDF stays in your browser except for the timestamp check (which only sends the hash + signature, never the document).
Don't want to trust this page — or need to verify offline? Get the standalone verifier — one HTML file that confirms a signed PDF is unaltered with no network and no AttachKit server. Save it; it keeps working forever.
Building a site? You can embed this verifier with a 4-line snippet so your visitors confirm a signed PDF inline — it runs entirely in their browser, with no callback to us.
No signed PDF handy?
New to AttachKit?
It's a privacy-first PDF toolkit — sign, fill or redact any document right in your browser. Nothing is uploaded, and no signup to start.
Verify a PDF signature, in your browser
Drop a signed PDF — or paste a link to one — and AttachKit re-checks the signature on your device: the document hash, the timestamp, and the passkey assertion. No account, nothing uploaded.
Nothing is uploaded
The whole thing runs in your browser — open your network tab and watch: your file never leaves your device. Most online tools round-trip your document through their servers.
Verifiable by anyone, free
An AttachKit signature can be checked by anyone, on any device, with no account and no callback to us — verification stays open even if the document leaves the platform.
Shows if anything changed
AttachKit re-computes the document's hash and compares it to the signed proof, so any edit since signing shows up as a failed check — tamper-evidence, not just a logo.