A signed document is only as legally sound as the person who signed it. If you can't prove the signer was who they claimed to be, that contract, NDA, or service agreement could fall apart the moment it's challenged. Yet most businesses still send documents with zero identity verification — just a link and a prayer.
Signer identity verification isn't a bureaucratic checkbox. It's the difference between an enforceable agreement and an expensive dispute. Tools like GoodSign build multiple verification layers directly into the signing workflow, so you're covered before a single signature lands.
Digital signatures are easy to fake if the process has no gates. Anyone with access to a recipient's email — a hacked inbox, a shared device, a forwarded link — can sign on their behalf. Without verification, you have no proof it was the right person.
Courts and regulators increasingly expect audit trails that confirm who signed, when, and how their identity was confirmed. ESIGN and eIDAS compliance both hinge on being able to demonstrate that. A timestamped email log isn't enough anymore.
The risk scales with what's at stake. A low-value quote might survive a disputed signature. A property lease, employment contract, or financial agreement almost certainly won't.
SMS verification for document signing works by requiring signers to confirm a one-time passcode sent to their mobile number before they can access the document. It's fast, familiar, and adds a critical second factor beyond email access alone.
The logic is straightforward: even if someone intercepts the signing link, they can't proceed without the code sent to the registered phone number. That's basic two-factor authentication applied to the document workflow.
For most business use cases — client contracts, vendor agreements, freelance SOWs — SMS verification hits the right balance of friction and security. It takes seconds for the signer and gives you a verified mobile number tied to the signing event in the audit trail.
Access codes work differently from SMS. Rather than sending a code automatically, you set a passphrase and share it with the signer through a separate channel — a phone call, a direct message, an in-person conversation.
This method is particularly useful when:
The separation matters. If someone gains access to your signer's inbox, they still can't open the document without a code that was never sent via email. It's a simple but effective gap in the attack surface.
For documents where the stakes are highest, passkey and biometric verification — including Face ID and fingerprint authentication on supported devices — ties the signing event to a verified physical identity.
This isn't overkill for every workflow. But when you're handling financial agreements, high-value service contracts, or anything with regulatory weight, being able to say "the signer authenticated with biometrics on their registered device" is a meaningful statement in any dispute.
These methods also reduce friction for repeat signers. Once set up, Face ID authentication is faster than typing a code — it just carries more identity weight.
| Method | What it confirms | Best for |
|---|---|---|
| Email only | Access to inbox | Low-risk, internal documents |
| SMS verification | Access to registered phone | Client contracts, vendor agreements |
| Access code | Knowledge of shared passphrase | Sensitive docs, unreliable SMS regions |
| Face ID / biometric | Physical identity on device | High-value, regulated agreements |
No single method is right for every document. Layering methods — SMS plus access code, for example — gives you stronger coverage for documents that genuinely need it without slowing down routine workflows.
The instinct to apply maximum security to everything sounds safe but creates unnecessary friction. Signers who hit too many gates before a routine approval document abandon the process — and then you're chasing them down anyway.
Match the verification level to the document's risk profile. A recurring supplier invoice approval might need email confirmation only. A new client contract should have SMS verification at minimum. A partnership agreement or financial disclosure warrants an access code and biometric if your platform supports it.
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