2026-07-07 | SMS, Notifications

Transactional SMS in the Verdocs API

Your signers live on their phones. For many workflows, a text message is the fastest way to get someone into a signing session. Verdocs supports transactional SMS—automated, event-driven text messages tied to envelope activity—alongside email. This article covers how that works today, what you need to enable it, and what to expect when you integrate.

What is transactional SMS?

Transactional SMS messages are automated texts Verdocs sends when something meaningful happens in a signing workflow. They are not marketing blasts. Each message is tied to a specific envelope event, includes a direct link to act, and is sent as a transactional message (with standard opt-out language appended).

For the time being, only one notification event sends SMS: recipient:invited—the initial invitation when a signer is asked to review and sign. Other lifecycle events (reminders, completion, cancellation, delegation, and so on) may send email notifications, but not SMS.

Unlike email notifications, SMS copy is not customizable through notification templates. Verdocs uses a fixed, concise format so messages stay readable on small screens and compliant with carrier expectations.

When does Verdocs send an SMS?

Supported events (today)

Verdocs routes SMS through the same notification system as email, but only one event is enabled for the SMS channel right now:

Event	Sends SMS?	Typical trigger
`recipient:invited`	Yes	A signer is invited to an envelope for the first time
`recipient:reminder`	No (email only)	Automated or manual reminder to sign
All other envelope events	No	Completion, cancellation, delegation, CC, etc.

If you are building against the API or debugging delivery, look for recipient:invited—that is the only event that will queue an outbound text today.

When that event fires and a signer is invited, Verdocs may deliver both an email and a text—if all of the conditions below are met.

Condition	Why it matters
Your organization has the SMS notifications entitlement	Without it, Verdocs skips SMS silently and still sends email. See Understanding Entitlements.
The recipient has a phone number on their record	SMS is only queued when `phone` is present at invite time.
The envelope is not `no_contact`	Bring-your-own-notification envelopes skip all outbound contact from Verdocs. See Bring-Your-Own Notification.
The recipient has not opted out of SMS	Recipients who reply `STOP`, `CANCEL`, or `END` will not receive further texts.

Reminders and resends use recipient:reminder, which is email-only. A new SMS is not sent on reminder or manual resend—even if the recipient has a phone number. Only the original recipient:invited event triggers a text.

What the message looks like

An invitation SMS follows this pattern:

Action required - {envelope name}
{sender name} invited you to review and sign a document.
Sign here: {signing link}
Reply STOP to cancel.

The signing link respects your Brand configuration: if the envelope uses a brand with an active custom app domain, the link points there; otherwise it uses the default Verdocs signing host. The link includes the recipient's role and a secure access key—the same style of deep link recipients receive by email.

How SMS fits into your integration

Provide a phone number on the recipient

When you create an envelope, include a phone value on each recipient who should be reachable by text. At least one of email or phone is required per recipient; many teams supply both so Verdocs can reach signers on either channel.

Use a valid, internationally formatted number (E.164). Verdocs normalizes phone numbers before sending. Invalid numbers are rejected at send time rather than retried indefinitely.

Email and SMS run in parallel

Invitations are not either/or. When a recipient has both email and phone, Verdocs queues both channels independently. That is why you may see envelope history entries for an email invite and an SMS invite for the same recipient—and why a missing SMS entitlement does not block email delivery.

SMS consent works differently from email:

Email recipients are treated as opted in by default for transactional messages.
SMS recipients are not auto-opted-in. Verdocs tracks consent per organization and phone number. A recipient who has not opted out (pending or opted_in) can receive messages; an opted_out recipient will not.

Every transactional message includes "Reply STOP to cancel." Inbound replies of STOP, CANCEL, or END mark the number as opted out for that organization. Future invitations to that number are suppressed for SMS while email continues to work.

Bring-your-own notification

If your application owns all signer communication, set no_contact: true on the envelope. Verdocs will not send invitation emails or SMS for that envelope. You are responsible for delivering the signing link yourself—typically via Start Signing Session or your own link construction.

Observability: history, certificates, and usage

Verdocs gives you several ways to confirm what happened—useful for support tickets and billing reconciliation.

Envelope history records whether a recipient was invited via email or SMS. In the dashboard, you will see messages like "Jane Doe has been invited via sms" alongside the email equivalent. When a recipient opens the document, history also notes whether they arrived through the email link or SMS link.

Completion certificates include an SMS Invitation indicator when the signer entered the workflow through a text-message link (alongside Email Invitation, In-Person Link, and In-App options). This helps demonstrate how the signer was reached during an audit.

Usage metering records each SMS invitation as sms_invite in your organization's usage metrics. Query Get organization usage or listen for the entitlement_used webhook event to feed internal billing or dashboards—especially valuable with organization hierarchies.

SMS Notifications