How to Implement Multi-Channel Delivery with the Docusign eSignature API

When you send an envelope using the Docusign eSignature API, a 201 Sent response means the integration worked. The envelope exists, your webhook will receive events, and the agreement is ready for signing.

But from a product or workflow perspective, the job isn't finished yet.

A transaction only converts when the recipient actually opens and signs the agreement. Until that moment, the agreement remains incomplete and your process is stalled.

This creates what we can call the conversion gap: the space between a successful API response and a completed agreement. Many integrations rely exclusively on email notifications to deliver agreements. But email is a crowded channel. If the notification gets buried in a busy inbox, the recipient may never see it.

Multi-Channel Delivery (MCD) closes this gap by treating agreement delivery as a redundancy problem rather than a single notification event. By sending Docusign SMS notifications or Docusign WhatsApp notifications, you move the agreement from a desktop inbox to the recipient's pocket, reducing friction and accelerating completion.

When to use simultaneous delivery

In earlier implementations, developers often had to choose a single delivery channel when sending an agreement notification. With the latest update to the Docusign eSignature API, you can use Simultaneous Delivery to notify a recipient through multiple channels in a single API request.

With Simultaneous Delivery, a single POST request can trigger both:

• Email notification

• SMS or WhatsApp notification

Sending notifications across multiple channels increases the likelihood that the recipient sees the agreement quickly. Instead of relying on a single inbox, notifications reach the recipient wherever they are, whether checking email at their desk or viewing messages on their phone.

This approach helps reduce the conversion gap between a successfully sent envelope and a completed agreement. By meeting recipients in the channels they already use, you increase visibility and shorten the time between delivery and signature.

Implementation: the additionalNotifications object

To enable multi-channel agreement delivery, add additionalNotifications to your signer object in your envelope request. A single API call can then trigger notifications across multiple channels.

{
  "emailSubject": "Contract for Signature",
  "recipients": {
    "signers": [
      {
        "email": "jane.doe@example.com",
        "name": "Jane Doe",
        "recipientId": "1",
        "additionalNotifications": [
          {
            "secondaryDeliveryMethod": "WhatsApp",
            "phoneNumber": {
              "countryCode": "49",
              "number": "5123456789"
            }
          }
        ]
      }
    ]
  },
  "status": "sent"
}

Add context to build recipient trust: emailBlurb logic

A common barrier to mobile signing is recipient trust. WhatsApp messages that contain links can easily be mistaken for spam. When recipients are unsure who sent the request or why they are receiving it, they may ignore the notification, which delays the signing process.

The Docusign eSignature API uses the existing emailBlurb field to populate the body of WhatsApp recipient notifications. You can include up to 250 characters of custom context, allowing you to personalize the message recipients see when they receive the notification.

For example: Hi Jane, here is the SOW for the office redesign we discussed today.

This small amount of context helps recipients quickly recognize the request and understand why they are receiving it. When the message feels familiar and relevant, recipients are more likely to open the agreement and complete the signature process. In practice, adding contextual messaging can help reduce hesitation, increase engagement, and accelerate agreement completion.

{
  "emailSubject": "Revised SOW: Office Redesign",
  "emailBlurb": "Hi Jane, here is the SOW for the redesign project we discussed today.",
  "recipients": {
    "signers": [
      {
        "email": "jane.doe@example.com",
        "name": "Jane Doe",
        "recipientId": "1",
        "additionalNotifications": [
          {
            "secondaryDeliveryMethod": "WhatsApp",
            "phoneNumber": {
              "countryCode": "49",
              "number": "15123456789"
            }
          }
        ]
      }
    ]
  },
  "status": "sent"
}

Note: The 250-character limit applies to the content used in the WhatsApp notification body. If your emailBlurb is longer, it will be truncated for mobile delivery. Keep the opening of your emailBlurb concise so the most relevant context appears within the character limit.

Scaling multi-channel delivery for enterprise workflows

Enterprise agreements are rarely simple one-to-one transactions. A board approval, procurement contract, or real-estate closing may involve multiple stakeholders who need to sign in sequence or in parallel. In these scenarios, maintaining signing momentum is critical.

The Docusign eSignature API supports up to 10 SMS or WhatsApp recipients per envelope through Multi-Channel Delivery. This allows you to notify all mobile-first recipients at the same time the envelope is sent rather than relying solely on email notifications.

If some signers primarily work from their desks while others rely on mobile devices, simultaneous delivery ensures everyone receives the signing request in the channel they are most likely to check. The result is fewer bottlenecks and faster agreement completion.

Prerequisites

Before implementing Multi-Channel Delivery, confirm the following:

• Your Docusign account plan includes SMS or WhatsApp permissions

• Your API Integrator Key is enabled for SMS or WhatsApp delivery

To verify or enable these permissions, check your Docusign Account Plan or contact your Account Executive. Attempting to send secondary notifications without the correct entitlements will result in the notification not being sent, even if the envelope itself is created successfully.

Troubleshooting Multi-Channel Delivery

When implementing Multi-Channel Delivery, most issues fall into a few predictable categories related to configuration, delivery permissions, or recipient data.

Secondary notification (SMS or WhatsApp) was not sent

If a signer does not receive an SMS or WhatsApp notification, the most common causes are:

• The phone number is missing or incorrectly formatted

• The secondaryDeliveryMethod value is misconfigured

• The account does not have SMS or WhatsApp permissions enabled for the API Integrator Key

• The recipient has opted out of SMS or WhatsApp notifications

Verify that the recipient object includes a properly formatted phone number and that the additionalNotifications object is correctly structured:

"additionalNotifications": [
  {
    "secondaryDeliveryMethod": "sms"
  }
]

If the envelope is successfully created but the secondary notification does not send, confirm that your API Integrator Key is enabled for SMS or WhatsApp delivery within your Docusign account plan.

WhatsApp or SMS delivery fails after the envelope is sent

If the envelope status is Sent but the mobile notification fails, the agreement itself is still valid. Email delivery remains the primary delivery method.

You can detect these issues programmatically using Docusign Connect webhooks. Subscribe to events such as RecipientDeliveryFailed to log delivery failures, trigger retries, or notify support systems if needed.

Recipients ignore SMS or WhatsApp signing notifications

In many cases, recipients hesitate to open mobile signing links because the message lacks recognizable context. The eSignature API automatically uses the emailBlurb value to populate the message body for WhatsApp notifications. Adding a short explanation helps recipients understand the request and trust the link.

Example: Hi Jane, here is the SOW for the office redesign we discussed today.

FAQ

Can I use different phone numbers for SMS and WhatsApp for the same signer?

No. The additionalNotifications object supports one phone number per recipient for secondary delivery. When configuring the notification, you specify whether that number should receive an SMS or WhatsApp message using the secondaryDeliveryMethod attribute.

If your workflow requires sending notifications to multiple numbers, you must model those recipients as separate signer objects.

Are there additional costs for WhatsApp or SMS notifications?

Multi-channel delivery may require specific plan entitlements. Check your Docusign Account Plan or contact your Account Executive to ensure your API Integrator Key has the WhatsApp/SMS permission enabled.

What happens if the WhatsApp delivery fails?

If a secondary notification fails, for example, due to an invalid phone number, the envelope status remains Sent as long as the email delivery succeeds. Developers can monitor delivery issues using Docusign Connect webhooks and subscribe to delivery failure events to detect and handle notification failures in their integration.

Next steps

Reducing the distance between Sent and Signed is a technical optimization that can drive significant business impact. To implement Multi-Channel Delivery in your integration:

• Review the documentation: Read the Multi-Channel Delivery Developer Guide for full API details and configuration options.

• Explore the SDK: See how to implement additionalNotifications using the Node.js or Python SDKs.

• Test in a developer environment: Log in to your Docusign developer account and try the JSON examples above to see Docusign SMS notifications and WhatsApp signing notifications in action.