Double Opt-In

Overview

Double opt-in requires new contacts to confirm their email address before they become subscribed. When enabled on a contact book, newly added contacts receive a confirmation email with a verification link. Only after clicking the link do they become fully subscribed. Why use double opt-in?

Ensures email addresses are valid and owned by the subscriber
Reduces bounce rates and spam complaints
Improves deliverability and sender reputation
Helps comply with email marketing regulations (GDPR, CAN-SPAM)

How it works

Contact is added

When a contact is added to a contact book with double opt-in enabled (via dashboard, API, or CSV import), they are created with a Pending status instead of being immediately subscribed.

Confirmation email is sent

A confirmation email is automatically sent to the contact with a unique verification link. The link is signed with HMAC-SHA256 and expires after 7 days.

Contact confirms

The contact clicks the verification link in the email and confirms their subscription on the confirmation page.

Contact is subscribed

The contact’s status changes from Pending to Subscribed and they will now receive your emails.

Enabling double opt-in

Via the dashboard

Go to Contacts and select a contact book
Click on the Double Opt-In tab
Toggle double opt-in on
Customize the confirmation email (optional)
Save your changes

Via the API

Create a contact book with double opt-in enabled:

curl -X POST https://app.usesend.com/api/v1/contactBooks \
  -H "Authorization: Bearer us_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Newsletter Subscribers",
    "doubleOptInEnabled": true,
    "doubleOptInFrom": "Newsletter <[email protected]>",
    "doubleOptInSubject": "Please confirm your subscription"
  }'

Or enable it on an existing contact book:

curl -X PATCH https://app.usesend.com/api/v1/contactBooks/{contactBookId} \
  -H "Authorization: Bearer us_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "doubleOptInEnabled": true
  }'

Contact statuses

When double opt-in is enabled, contacts have three possible statuses:

Status	Description
Subscribed	Contact has confirmed their subscription and will receive emails
Pending	Contact has been added but hasn’t confirmed yet
Unsubscribed	Contact has explicitly unsubscribed

Contacts with Pending status will not receive campaign emails. They will only receive the double opt-in confirmation email.

Customizing the confirmation email

You can customize three aspects of the confirmation email:

From address

Set a custom sender address for confirmation emails. The address must use one of your verified domains.

{
  "doubleOptInFrom": "Newsletter <[email protected]>"
}

If not set, the confirmation email will be sent from the first available verified domain.

Subject line

Customize the email subject. The default is “Please confirm your subscription”.

{
  "doubleOptInSubject": "Confirm your subscription to our newsletter"
}

Email template

The confirmation email body can be customized using the useSend email editor (via the dashboard) or by providing the editor JSON content via the API.

Template variables

The following variables can be used in the confirmation email template:

Variable	Description
`{{doubleOptInUrl}}`	The confirmation link (required)
`{{email}}`	The contact’s email address
`{{firstName}}`	The contact’s first name
`{{lastName}}`	The contact’s last name

The {{ doubleOptInUrl }} variable is required in the email template. The confirmation email cannot be saved without it. This ensures every confirmation email contains a working verification link.

Resending confirmation emails

If a contact hasn’t confirmed their subscription, you can resend the confirmation email from the dashboard:

Go to your contact book and find the pending contact
Click the Resend button next to the contact

Each resend generates a new confirmation link with a fresh 7-day expiration window.

Best practices

Best practice	Why it helps
Set up a verified domain first	Double opt-in emails need a verified domain before they can be sent
Keep the confirmation email simple	Makes it easier for subscribers to understand and complete the confirmation step
Use a recognizable from address	Reduces the chance of the confirmation email being ignored or marked as spam
Monitor pending contacts	Helps you spot low confirmation rates and improve your signup flow

Getting Started

Self Hosting

Guides

Overview

How it works

Enabling double opt-in

Via the dashboard

Via the API

Contact statuses

Customizing the confirmation email

From address

Subject line

Email template

Template variables

Resending confirmation emails

Best practices

​Overview

​How it works

​Enabling double opt-in

​Via the dashboard

​Via the API

​Contact statuses

​Customizing the confirmation email

​From address

​Subject line

​Email template

​Template variables

​Resending confirmation emails

​Best practices

Overview

How it works

Enabling double opt-in

Via the dashboard

Via the API

Contact statuses

Customizing the confirmation email

From address

Subject line

Email template

Template variables

Resending confirmation emails

Best practices