How does SMS work in Verdocs signing?
The SMS add-on does two jobs. It texts signers a one-time code to enter before the document opens, which shows they hold the phone number you have on file. And it texts them their invitation to sign, with a direct link, so they can act from their phone.
What does an SMS access code prove?
That the signer has the phone number you have on file. The code is six digits and valid for one hour, and the signer can request a new one. It proves access to a phone, not identity: when you need to know who the person is, use KBA or ID Scan, on their own or alongside the code.
What texts do signers receive?
Their invitation to sign, with a direct link into the signing session. Reminders, completion notices and other updates go by email. The text is a transactional message tied to the document, not marketing, and it carries standard opt-out language. The wording uses a fixed, short format so it reads well on a small screen, and you can set the sender name your signers see.
When should you use it?
When your signers live on their phones and an email is likely to sit unread, or when you want a second factor on top of the emailed link without adding an identity check. For documents where a disputed signature would be expensive, pair it with or replace it by KBA or ID Scan.
What do you need to send texts?
A phone number on the recipient when you invite them. Signers who opt out of texts are not texted, and documents where your own system sends the notifications do not get texts from Verdocs.
Where does it work?
Texts reach signers in most countries. Some countries require a registered sender before messages are delivered, so tell us where your signers are and we will confirm coverage before you go live.
What does it cost?
$0.25 per message, for each text, including each access code. It is available on paid plans and activated for your account on request, with no setup fee.
How do developers turn it on?
For access codes, add SMS to a recipient's authentication methods (auth_methods) through the API. For invitations, once SMS is activated for your account, Verdocs texts any recipient who has a phone number on their record. The SMS Notifications page in the developer documentation covers the conditions and opt-outs.
Going deeper on SMS
Is Knowledge-Based Authentication Enough for Remote Signing?
IRS Publication 1345 requires KBA and also points at a NIST assurance level. Reading both documents carefully shows why that question has no clean answer.
Read the post2026-10-09Matching Signer Verification to the Insurance Transaction
Not every insurance document needs the same signer check, and document type alone should not decide it. A starting matrix for matching checks to the signer, the requested action, and the money involved.
Read the postRelated
Prices sit with the other identity add-ons on the pricing page.
Talk to us about itGeneral information, not legal advice; consult your own advisors for the signature level your documents require.