Sailthru (part of Marigold, formerly CM Group) is an enterprise B2C personalization platform serving media, retail, and publishing brands with predictive AI-driven content recommendations, email, and web personalization. The unsubscribe mechanism uses the {unsubscribe_link} Zephyr merge tag in email templates, and Sailthru emits RFC 8058 headers automatically for authenticated sending domains. Consent is tracked at the profile level with per-list opt-out and predictive lifetime value modeling that informs re-engagement strategy. This guide covers the tag, the Zephyr templating system, and how to verify the setup end to end.
Sailthru unsubscribe link
| Tag syntax | {unsubscribe_link} |
| Placement | Auto-embedded in default email footer |
| Scope | Profile-level opt-out with per-list granularity |
| Config path | Settings > Email > Sender configuration |
| RFC 8058 one-click | Yes, automatic for authenticated sending domains |
How to add the unsubscribe tag in Sailthru
Place the merge tag exactly as shown below in the email template. Sailthru replaces it at send time with a signed URL scoped to the recipient and campaign.
{unsubscribe_link}For custom HTML templates, wrap the tag in an anchor to render a proper hyperlink in the delivered email:
<a href="{unsubscribe_link}">Unsubscribe from this list</a>Auto-embedded in default email footer
Yes, automatic for authenticated sending domains The recipient's mailbox provider (Gmail, Yahoo) uses the List-Unsubscribe-Post header to expose the native one-click button on the message. Requires domain authentication with DKIM and DMARC.
Sailthru Zephyr templating language uses distinct merge tag syntax from other Marigold platforms (Campaign Monitor, Emma, Cheetah Digital). Marketing teams migrating campaigns between Marigold products must convert merge tags manually. Sailthru {unsubscribe_link} does not work in Campaign Monitor or Cheetah Digital templates and vice versa, causing template failures if not converted during cross-platform migrations.
Testing your Sailthru unsubscribe link
- Send a test message to a controlled Gmail address you own via the Sailthru campaign preview action
- Click the footer unsubscribe link and confirm the opt-out on the landing page
- Check the subscriber or contact record: the status should be Unsubscribed within seconds
- Verify the RFC 8058 headers in Gmail: open the message, click three dots, then Show original. Look for
List-UnsubscribeandList-Unsubscribe-Post: List-Unsubscribe=One-Click
Want the full 222-platform reference?
See the pillar guide with the compliance landscape, the RFC 8058 deep dive, and the unsubscribe tag for every ESP: How to add an unsubscribe link: the complete 2026 guide →
How to add the Sailthru unsubscribe link (step by step)
Sailthru templates include the unsubscribe link in the default footer, but custom Zephyr templates require the tag inserted manually.
- Open your Sailthru template in the Content Editor.
- Add or edit a text block in the footer where the unsubscribe link should appear.
- Insert the Zephyr merge tag
{unsubscribe_link}. Sailthru replaces it at send time with a signed URL scoped to the profile. - Wrap it in an anchor:
<a href="{unsubscribe_link}">Unsubscribe</a>. - Configure the sending domain under Settings > Email > Sender configuration. SPF and DKIM must be verified.
- Send a test to a seed address and verify the rendered link routes to the Sailthru-hosted preference center.
Zephyr templating and cross-Marigold portability
Sailthru Zephyr templating language uses distinct merge tag syntax from other Marigold platforms (Campaign Monitor, Emma, Cheetah Digital). Marketing teams migrating campaigns between Marigold products must convert merge tags manually. Sailthru {unsubscribe_link} does not work in Campaign Monitor or Cheetah Digital templates and vice versa, causing template failures if not converted during cross-platform migrations. This templating fragmentation is a common pain point for Marigold customers running multiple Marigold products for different brand or program requirements.
RFC 8058 one-click headers
Sailthru added RFC 8058 one-click unsubscribe automatically ahead of the Google and Yahoo February 2024 requirements. The List-Unsubscribe and List-Unsubscribe-Post headers inject on every marketing send from domains authenticated under Settings > Email > Sender configuration. SPF and DKIM records must be verified. Enterprise media and retail accounts running multiple brand sending domains configure each domain independently with per-domain RFC 8058 status visible in the domain reputation dashboard.
Predictive AI and re-engagement of at-risk subscribers
Sailthru distinguishing feature is predictive AI: the platform models lifetime value, purchase probability, and disengagement risk per profile. Profiles flagged as at-risk of unsubscribing can be routed to re-engagement campaigns before they actively opt out, improving list retention. When a profile does unsubscribe, the AI model learns from the pattern to refine future risk predictions. This predictive layer sits above the standard consent tracking, letting media and retail brands proactively address disengagement rather than react to opt-outs.
Frequently Asked Questions
What is the Sailthru unsubscribe tag?
The Zephyr merge tag is {unsubscribe_link}. Sailthru replaces it at send time with a signed URL scoped to the profile. Use it inside an anchor: <a href="{unsubscribe_link}">Unsubscribe</a>.
Can I copy Sailthru templates to other Marigold products?
Not directly. Sailthru Zephyr merge tags differ from Campaign Monitor, Emma, and Cheetah Digital syntax. Cross-Marigold template migrations require manual merge tag conversion for unsubscribe links, personalization variables, and other dynamic content.
Does Sailthru support one-click unsubscribe for Gmail and Yahoo?
Yes, automatically for authenticated domains. Sailthru injects List-Unsubscribe and List-Unsubscribe-Post headers on every marketing send from domains verified under Settings > Email > Sender configuration.
Can Sailthru predict which subscribers will unsubscribe?
Yes via predictive AI. Sailthru models disengagement risk per profile based on engagement history, purchase behavior, and content preferences. At-risk profiles can be routed to re-engagement campaigns proactively before they actively opt out.
Can I resubscribe a profile who unsubscribed from Sailthru?
Not through the API without explicit consent capture. Sailthru enforces permanent suppression on opt-outs. Reactivation requires the profile to re-opt in through a Sailthru-hosted signup form or documented consent update.
About the Author
Alaa · LinkedIn
Email infrastructure specialist with 8+ years of hands-on experience in SMTP, deliverability, and email verification. I’ve configured and troubleshot mail systems across Postfix, Exchange, and cloud relays, managed IP reputation and warmup campaigns, and built verification pipelines processing millions of addresses. My work spans DNS authentication (SPF, DKIM, DMARC, BIMI), bounce handling, blocklist monitoring, and compliance frameworks including CAN-SPAM and GDPR. I write every article on SMTPedia to give email professionals, developers, and marketers the accurate, RFC-grounded reference they need.
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