How can I verify whether a recipient email address actually exists before sending an envelope?

Hi everyone,

I’m integrating DocuSign with a C# application. Before sending an envelope, I want to validate the recipient’s email address.

Currently, I can perform basic format validation, for example checking whether the email has a valid format such as user@company.com.

However, I would like to know if there is a recommended way in the DocuSign API/SDK to determine whether the recipient email address actually exists and is deliverable before sending the envelope.

For example:

• Can DocuSign validate whether the mailbox actually exists?

• Is there an API or recommended approach to check email deliverability before creating/sending the envelope?

• If the email is invalid or undeliverable, can I detect this before the envelope is sent?

Any guidance on the recommended approach would be appreciated.

Thanks!