Cryptographic proof you signed a specific document at a specific time — self-contained, independent of any platform, anchored on public chains.
Every time you sign with DocuSign, Adobe Sign, or HelloSign, you're trusting a company to keep your signature valid. If they shut down, raise prices, get breached, or lose your data, your proof disappears.
Open a document, tap Sign, confirm with Face ID or fingerprint. Done.
Send a verification link or code to anyone who needs proof.
They open the link, see the ✓. No account, no app — the math proves it.
A SignedBundle is a self-contained JSON file. It carries the document hash, the signer's key chain, a blockchain-anchored timestamp, and proof the signing key was valid. Anyone can verify it, forever.
Not all signatures carry the same weight. Mark lets you build trust progressively, each tier keeping the assurance below it.
Create an identity in two minutes. Cryptographic proof is strong, but identity is unverified. Good for everyday signing between known parties.
Get endorsed by a Tier 3 organization. An org vouches for the signer — verified through their process and signed with an org endorsement.
Visit a notary who verifies your government ID. Equivalent to a notarized wet signature under US federal law.
Notary attestation is pending legal review of the attestation template.
Published to Polygon via relay
We relay the tx
Public calendars
Verification code
| Mark | DocuSign | |
|---|---|---|
| Price | Free tier, Pro $5/mo | $15/mo |
| You own your signatures | ✓Self-contained proof | Platform owns verification |
| Survives vendor shutdown | ✓Blockchain-anchored | No |
| Document uploaded to vendor | ✓Only if you choose, for co-sign | Yes, always |
| Independent verification | ✓Anyone, anywhere, forever | Need DocuSign |
| On-chain timestamp proof | ✓Bitcoin + Polygon | No |
| Hardware key support | ✓YubiKey 5C NFC | No |
The Mark Signing Protocol (MSP) is published, versioned, and anyone can implement it. A SignedBundle is a JSON file. The verification algorithm is published. The proof chain resolves to public blockchains. If Mark the company disappeared tomorrow, every signature ever made would still verify.
Mark satisfies the US ESIGN Act and UETA (49 states + DC), the EU's eIDAS regulation (Advanced Electronic Signature), and equivalent laws in the UK, Australia, and Singapore. At Tier 3, a Mark signature is equivalent to a notarized wet signature under US federal law.
Exceptions: wills, codicils, testamentary trusts, and certain family-law documents are excluded in most jurisdictions.