An NDA is the most-signed document there is and the one most likely to be needed as evidence years later, long after everyone has forgotten the deal. Send it in about a minute, and get back a sealed copy that proves itself.
NDAs get filed and forgotten. The moment one matters is years later, usually in a dispute, when someone needs to show what was agreed and that it has not been edited since. That is a question about evidence, not about signatures.
Every completed MostlySign NDA carries a certificate of completion inside the PDF — who signed, the email the invitation went to and was opened from, timestamps to the second in UTC, the IP each action came from, the signer's explicit consent to sign electronically, and a cryptographic hash of the exact bytes that were signed.
Then the whole thing is sealed with a PAdES signature and an RFC 3161 timestamp, so a later edit — a changed date, a changed term, a changed name — breaks the seal visibly in any validator. And because the proof is embedded in the file, the signed NDA stays checkable if you leave us, if the deal moves to another company, or if nobody involved still has an account.
All of these work on the free plan except where noted.
Upload the PDF, drop a signature field, add the other side's email. Three a month are free.
Send an NDA free