What This Feature Does
A Double Opt-In list requires subscribers to confirm their email address by clicking a verification link before they can receive your campaigns. This two-step process ensures you're building a high-quality, engaged list of people who genuinely want to hear from you.
When and Why You'd Use Double Opt-In
Use Double Opt-In for:
External or purchased lists where you're unsure if contacts actively want to hear from you
Cold leads who may not remember signing up
Old, dormant lists you're re-activating after months or years
High-risk sources like co-registration, lead magnets from third parties, or contest entries
Maximum deliverability when sender reputation is critical
GDPR compliance in the EU (double opt-in is considered best practice under GDPR)
Use Single Opt-In for:
Past customers who already have a relationship with you
Event attendees or webinar registrants who explicitly signed up
Contacts who just completed a purchase or transaction
Warm leads where immediate follow-up is more important than verification
Speed-sensitive campaigns where you need to email quickly
Why Double Opt-In Matters:
Benefits:
✅ Higher quality list: Only engaged, interested contacts receive your emails
✅ Better deliverability: Email providers trust verified lists more, improving inbox placement
✅ Lower spam complaints: People who confirm their subscription are less likely to mark you as spam
✅ Cleaner list: Invalid, fake, or typo emails are automatically filtered out
✅ Legal protection: Provides clear proof of consent if questioned
Trade-offs:
❌ Lower conversion rate: 50-70% of form submitters actually click the confirmation link
❌ Slower growth: Adds an extra step between signup and subscription
❌ Potential friction: Some legitimate subscribers may abandon before confirming
Best practice: Use Double Opt-In when list quality and deliverability are more important than list size.
How Double Opt-In Works: The Complete Flow
Understanding the process helps you design a better user experience:
Step 1: Contact Added to List (Unconfirmed Status)
SendX immediately adds the contact to your Double Opt-In list
The contact is marked as "Unconfirmed"
⚠️ Important: Unconfirmed contacts count toward your plan limit but cannot receive campaigns
Step 2: Confirmation Email Sent Automatically
SendX instantly sends a confirmation email to the contact
This email contains a "Confirm Here" button (or custom text you choose)
The button includes an automatic verification link
Step 3: Contact Clicks Confirmation Link
Contact clicks the button in their email
They're taken to a confirmation page in their browser (customizable)
Their status changes from "Unconfirmed" to "Confirmed"
✅ They can now receive all campaigns sent to this list
If Contact Does NOT Click:
They remain in your list with "Unconfirmed" status
They will not receive any campaigns (SendX automatically excludes them)
They still count toward your plan limit
The confirmation link remains valid forever—they can confirm anytime in the future
Step-by-Step: Creating a Double Opt-In List
Step 1: Navigate to Lists
Click Audience in the top navigation menu
Select Lists from the dropdown
Step 2: Create a New List
Click Create List (yellow button at the top right)
A form will open with several sections
Step 3: Name Your List
In the List Name field, enter a clear, descriptive name
Examples: "Blog Subscribers," "Newsletter Signup," "Lead Magnet Downloads"
This name is only visible to you—contacts won't see it
Step 4: Configure Advanced Settings
Scroll down to the Advanced Setting section
Find List Type
Click the dropdown menu (default is "Single Opt-in")
Select "Double Opt-in"
Step 5: Customize the Confirmation Email
This is the email subscribers receive immediately after submitting the form, asking them to verify their subscription.
Who is this from? (Required)
Click the dropdown and select your verified sender profile
This determines what appears in the "From" field of the recipient's inbox
Format example: "Gavin Belson < gavin.belson@hooli.marketing >"
Pro tip: Use a recognizable sender name (your brand or personal name) to increase open rates
Subject (Required)
Write the subject line for your confirmation email
Keep it clear and action-oriented
Good examples:
"Please confirm your subscription to [Your Brand]"
"One more step: Verify your email address"
"Confirm to be a part of [Your Brand]"
Click the Personalization dropdown to add dynamic fields like {{.FirstName}}
Available tokens: {{.FirstName}}, {{.LastName}}, {{.Email}}, and any custom fields
Email Body Below the subject line, you'll see a visual email editor with a preview of your confirmation email.
Default template includes:
Your SendX logo or custom logo
Personalized greeting: "Hi {{.FirstName}},"
Clear call-to-action text
"Confirm Here" button (green, prominent)
Signature (e.g., "Cheers, Team SendX")
Powered by SendX footer (automatic)
To customize the email:
Click the Edit button (located at the bottom of the email preview or within the editor)
The full email editor will open
Make any changes you want:
Change the greeting text: Modify "Hi {{.FirstName}}," to your preferred style
Edit the body copy: Write your own message explaining what they're subscribing to
Customize the button:
Change text from "Confirm Here" to something else (e.g., "Yes, Subscribe Me!", "Verify My Email")
⚠️ Critical: Do NOT remove the button—it contains the automatic verification link
You can change colors, size, and styling
Add your logo: Click to upload your brand logo at the top
Adjust fonts and colors: Match your brand style
Add images: Include graphics, product photos, or icons
Use the Personalization dropdown to insert dynamic fields anywhere in the email body
Preview your changes in real-time
Save the template
⚠️ Important Warning:
The confirmation button automatically includes the verification link—don't remove it
If you delete the button, subscribers won't be able to confirm, and the process will fail
You can edit everything else, but keep the button intact
Step 6: Customize the Success Page (Optional)
After contacts click the confirmation link, they see a confirmation page in their browser.
To customize this page:
Look for a "Success Page" setting (may be in the same editor or a separate section)
Click the Edit button (located at the bottom of the email preview or within the editor)
The full email editor will open
Make any changes you want.
Step 7: Save Your List
Review all settings
Click Create or Save List (button at the bottom)
Your Double Opt-In list is now active!
What NOT to Include: The Thank You Email
You may notice a "Thank You Email Setting" option on the list creation screen with a checkbox that says:
"Send automated thank you e-mail once user has subscribed to this list"
For Double Opt-In lists, leave this UNCHECKED.
Why?
You're already sending a confirmation email immediately after signup
Sending BOTH a confirmation email and a thank you email is excessive and may irritate subscribers
The confirmation email serves as your initial contact
When to use Thank You Emails:
✅ For Single Opt-In lists where there's no confirmation email
✅ As a welcome message for immediate, confirmed subscribers
❌ NOT for Double Opt-In lists (too many emails)
Testing Your Double Opt-In List
Before connecting your list to live forms, test the entire flow to ensure everything works correctly.
How to Test:
Step 1: Use a real email address
Use your own email or a team member's email
Don't use fake or temporary email addresses—you need to receive and click the confirmation email
Step 2: Submit a test form
Create a test form connected to your Double Opt-In list (or use an existing one)
Fill it out with your test email address
Submit the form
Step 3: Check for the confirmation email
Open your inbox
Look for the confirmation email (check spam/junk if you don't see it)
Verify:
Subject line displays correctly
From name/email is correct
Personalization tokens populate properly (e.g., {{.FirstName}} shows actual name)
Email body looks good on desktop and mobile
Button text is correct
Logo and branding are correct
Step 4: Click the confirmation button
Click the "Confirm Here" (or custom) button
Verify you're taken to the confirmation page
Check that the confirmation page displays your custom message (if you set one)
Step 5: Verify in SendX
Go back to SendX
Navigate to Audience → Contacts
Find your test email address
Check that the contact status changed from "Unconfirmed" to "Confirmed"
Step 6: Test a campaign (optional)
Create a test campaign targeting your Double Opt-In list
Send it to yourself
Confirm you receive the campaign now that you're confirmed
Step 7: Clean up
Delete your test contact or move them to a "Test Contacts" segment
Or keep them on the list if you want to receive future emails
Managing Unconfirmed Contacts
Viewing Unconfirmed Contacts
To see who submitted forms but hasn't confirmed yet:
Go to Audience → Segments
Create a new segment
Set conditions:
Condition 1: "Is in list" → Select your Double Opt-In list
Condition 2: "Subscription Status" → "Unconfirmed."
This shows everyone who needs to confirm
What to Do With Unconfirmed Contacts
Option 1: Wait patiently
Some people confirm hours or even days after signing up
The confirmation link never expires, so they can confirm anytime
Option 2: Send a reminder (carefully)
⚠️ Caution: Technically, unconfirmed contacts haven't given full consent yet
If you must remind them, use a different channel (if available) or wait at least 3-7 days
Keep reminders minimal (1-2 maximum) to avoid irritating legitimate users
Option 3: Clean them out periodically
After 30-60 days, unconfirmed contacts are unlikely to ever confirm
Export them for your records
Delete them to free up space in your plan limit
Remember: Unconfirmed contacts still count toward your billing
Option 4: Add them to another list (advanced)
If you have a Single Opt-In list, you could move unconfirmed contacts there
This immediately confirms them across all lists in SendX
⚠️ Use cautiously: Only do this if you have another legitimate reason to believe they want your emails
Confirmed Contacts Across Multiple Lists
Important behavior to understand:
Once a contact confirms their subscription on ONE list, they become "confirmed" across your entire SendX account.
What this means:
If a confirmed contact is added to another Double Opt-In list (via import, API, or another form), they do NOT need to re-confirm
They'll immediately be marked "Confirmed" on the new list and can receive campaigns
This prevents annoying subscribers with multiple confirmation emails
Exception:
If a contact has globally unsubscribed from your account, they remain unsubscribed even if added to new lists
They would need to manually re-subscribe through a form
Converting Existing Lists: Single to Double Opt-In
Can You Change an Existing List?
Yes! You can change a Single Opt-In list to Double Opt-In (or vice versa) at any time.
What happens to existing contacts:
Changing Single → Double Opt-In:
All existing contacts remain "Confirmed"
They are NOT sent confirmation emails retroactively
Only NEW subscribers added after the change go through the double opt-in process
No disruption to current subscribers
Changing Double → Single Opt-In:
All contacts (confirmed and unconfirmed) remain on the list
Unconfirmed contacts immediately become "Confirmed" and can receive campaigns
New subscribers are confirmed instantly without verification
How to change list type:
Go to Audience → Lists
Click on the list name
Click Edit List
Scroll to Advanced Setting → List Type
Select "Double Opt-in" or "Single Opt-in"
Click Save List
Common Questions and Troubleshooting
Q: My confirmation email is going to spam. How do I fix this?
A: Several factors can cause this:
1. Verify your sending domain:
Go to Admin → Sender Settings
Ensure your domain is authenticated (SPF, DKIM records)
Use your business domain, not a free provider like Gmail or Yahoo
2. Improve email content:
Avoid spam trigger words ("Free!", "Act Now!", excessive exclamation marks)
Include a physical mailing address
Balance text and images (too many images can trigger spam filters)
Don't use ALL CAPS in subject lines
3. Test with multiple email providers:
Send test confirmations to Gmail, Outlook, Yahoo, etc.
See which providers have issues
Adjust content accordingly
4. Warm up your sending domain:
If you're new to SendX or have a new domain, start slowly
Send to engaged contacts first
Gradually increase volume
5. Contact SendX Support:
They can check your sender reputation
Investigate deliverability issues
Provide specific recommendations
Q: People are clicking "Confirm," but their status isn't changing. What's wrong?
A: Troubleshooting steps:
Check if the button link is working:
Test by clicking it yourself
Ensure it redirects to a SendX confirmation page
Verify the contact exists:
Go to Audience → Contacts
Search for the email address
Check if they're on the correct list
Look for browser/cookie issues:
Some browsers or privacy settings block confirmation links
Ask the contact to try a different browser
Check if they have cookies disabled
Check for email client issues:
Some email clients (especially older Outlook versions) don't render links properly
Ask the subscriber to right-click the button and "Copy Link," then paste it in their browser
Contact SendX Support:
Provide the specific email address
Share when they clicked the link
Support can investigate the backend logs
Q: I accidentally deleted the confirmation button. How do I get it back?
A:
If you haven't saved yet:
Click "Cancel" or refresh the page
Start over with the default template
If you already saved:
Edit the list again
Go to the confirmation email editor
Look for an option to "Reset to Default Template" or "Restore Original"
If that option doesn't exist, contact SendX Support—they can restore the default button for you
Prevention tip: Always test your customizations before finalizing!
Q: What's a good confirmation rate? How do I improve it?
A:
Industry averages:
50-70% is typical for double opt-in
Below 40% suggests issues with your process
Above 80% is excellent
How to improve confirmation rates:
1. Optimize your form messaging:
Set expectations: "Check your email to confirm your subscription."
Tell them what to look for: "Look for an email from [Your Brand Name]."
2. Improve the confirmation email:
Use an engaging subject line: "You're almost subscribed! Confirm now"
Make the email mobile-friendly (many people check email on phones)
Keep it simple—don't bury the confirmation button in paragraphs of text
Use a clear, action-oriented button: "Yes, Subscribe Me!" performs better than generic "Confirm."
3. Send the email immediately:
SendX does this automatically, but timing matters
The faster the confirmation email arrives, the more likely people will act
4. Set expectations on the form:
Add text like "Please check your email to complete signup."
This primes people to expect and look for the confirmation email
5. Follow up (carefully):
After 24-48 hours, consider a gentle reminder
"Did you forget to confirm? Click here to complete your subscription."
Limit reminders to 1-2 to avoid being pushy
Q: Can I bypass double opt-in for specific contacts (like VIP customers)?
A: Not automatically through imports or API, but you have workarounds:
Option 1: Add them to a Single Opt-In list instead
Create a separate Single Opt-In list for VIPs or known contacts
Import them there—they're immediately confirmed
Option 2: Manually confirm them
Add the contact to your Double Opt-In list (they'll be marked "Unconfirmed")
Click the confirmation link yourself on their behalf
⚠️ Only do this for contacts you're absolutely certain want your emails (past customers, colleagues, etc.)
Option 3: Use a different list type based on source
Double Opt-In lists for cold/external sources
Single Opt-In lists for warm/known sources
Q: Do unconfirmed contacts count toward my plan limit?
A: Yes, unconfirmed contacts count toward your billing.
This is why it's important to periodically clean out unconfirmed contacts who never verified:
Create a segment of unconfirmed contacts (filter by "Subscription Status = Unconfirmed")
Export them for your records
After 30-60 days, delete contacts who still haven't confirmed
This frees up space in your plan limit
Q: I imported a list to a Double Opt-In list. Will they all receive confirmation emails?
A: It depends:
If they're NEW to your SendX account:
Yes, they'll be added as "Unconfirmed."
They'll receive confirmation emails
If they're ALREADY confirmed in SendX (on another list):
They're immediately marked "Confirmed" on the new list
No confirmation email is sent
Best practice for imports:
If you're importing a list you're unsure about, use Double Opt-In
If you're importing known, consented contacts (like past customers), use Single Opt-In
Q: Can I customize the confirmation page that appears after someone clicks the link?
A: Yes! Look for settings related to:
"Success Page"
"Confirmation Page"
"Post-Confirmation Message"
These may be in:
The list settings (under Advanced Settings)
The form builder (if forms control the confirmation page)
A separate "Pages" or "Templates" section
What to include on your confirmation page:
Thank you message: "Thanks for confirming! You're all set."
Next steps: "Check your inbox for our welcome email."
Call-to-action: Link to your blog, resources, or a special offer
Social media links: Encourage them to follow you
Branding: Logo and consistent visual style
Contact SendX Support if you can't find the confirmation page settings—they can guide you.
Q: My list is growing slowly with Double Opt-In. Should I switch to Single Opt-In?
A: Consider your priorities:
Stick with Double Opt-In if:
Deliverability and sender reputation are critical
You're targeting cold or uncertain audiences
You value quality over quantity
You're in the EU or targeting EU subscribers (GDPR)
Switch to Single Opt-In if:
You need faster list growth
You're confident in your contact sources (warm leads, past customers)
Immediate follow-up is essential (time-sensitive offers)
You're willing to accept lower engagement rates in exchange for larger list size
Hybrid approach:
Use Double Opt-In for external/cold sources
Use Single Opt-In for warm/known sources
Segment your lists accordingly
Quick Reference: Double Opt-In Checklist
Use this checklist when creating a Double Opt-In list:
Setup:
[ ] Go to Audience → Lists → Create List
[ ] Name your list clearly
[ ] Select List Type: Double Opt-in
[ ] Choose sender (From Name/Email)
[ ] Write a clear subject line (use personalization if desired)
[ ] Click Edit to customize the confirmation email
[ ] Verify the confirmation button is present and styled correctly
[ ] Add your logo and branding
[ ] Write compelling body copy explaining what they're subscribing to
[ ] Customize the confirmation page (optional)
[ ] Do NOT enable "Thank You Email" (unnecessary for Double Opt-In)
[ ] Click Create or Save List
Testing:
[ ] Create or connect a form to the list
[ ] Submit the form with your own email address
[ ] Check inbox for confirmation email
[ ] Verify subject, sender, and content display correctly
[ ] Click the confirmation button
[ ] Verify the confirmation page displays correctly
[ ] Check SendX to confirm contact status changed to "Confirmed"
[ ] Send a test campaign to ensure you receive it
[ ] Clean up test contact
Maintenance:
[ ] Monitor confirmation rates (aim for 50-70%+)
[ ] Periodically export and delete unconfirmed contacts (after 30-60 days)
[ ] Review spam folder deliverability
[ ] Update messaging if confirmation rates drop
Need Help?
If you're having trouble setting up Double Opt-In lists or need assistance with:
Improving confirmation rates
Fixing deliverability issues
Customizing confirmation emails or pages
Deciding between Single and Double Opt-In
Migrating existing lists
Contact SendX Support for personalized guidance. They can help you optimize your list setup for maximum engagement and deliverability.
Pro Tip: Always preview your confirmation email on both desktop and mobile before launching. Over 50% of emails are opened on mobile devices, so ensure your button is large enough to tap easily and your message displays correctly on small screens!