Mailrelay is a Spanish email marketing platform known for one of the most generous free tiers in the industry (up to 80,000 emails/month on the free plan for verified senders). The unsubscribe mechanism uses the {{unsubscribe_url}} merge tag in the drag-and-drop editor. Mailrelay emits RFC 8058 headers automatically for authenticated domains and enforces the unsubscribe presence at send time. This guide covers the tag, the group and list suppression model, and how to verify the setup end to end.
Mailrelay unsubscribe link
| Tag syntax | {{unsubscribe_url}} |
| Placement | Auto-embedded in every campaign footer, enforced at save |
| Scope | Per-Group opt-out with account-wide suppression option |
| Config path | Account > Sending Domains |
| RFC 8058 one-click | Yes, automatic for authenticated domains including free tier |
How to add the unsubscribe tag in Mailrelay
Place the merge tag exactly as shown below in the email template. Mailrelay replaces it at send time with a signed URL scoped to the recipient and campaign.
{{unsubscribe_url}}For custom HTML templates, wrap the tag in an anchor to render a proper hyperlink in the delivered email:
<a href="{{unsubscribe_url}}">Unsubscribe from this list</a>Auto-embedded in every campaign footer, enforced at save
Yes, automatic for authenticated domains including free tier 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.
Mailrelay free tier (80,000 emails per month for verified senders) includes RFC 8058 automatic header injection, unlike some competitors that gate one-click compliance behind paid tiers. Free tier accounts still need SPF and DKIM verified under Account > Sending Domains for headers to activate. Unverified free tier accounts fall back to shared infrastructure without one-click support.
Testing your Mailrelay unsubscribe link
- Send a test message to a controlled Gmail address you own via the Mailrelay 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 Mailrelay unsubscribe link (step by step)
Mailrelay campaigns include a default footer with the unsubscribe link, and Mailrelay refuses to save a campaign without the tag anywhere in the body. Custom HTML templates require the tag inserted manually.
- Open your campaign or template in the Mailrelay editor.
- Add or edit a text block in the footer where the unsubscribe link should appear.
- Insert the merge tag
{{unsubscribe_url}}. Mailrelay replaces it at send time with a signed URL unique per subscriber. - Wrap in an anchor with your preferred label:
<a href="{{unsubscribe_url}}">Unsubscribe</a>. Localize the label if you send in multiple languages. - Add the physical postal address block. Mailrelay reads it from Account Settings > Sender Details.
- Save the campaign. Mailrelay validates the tag presence and blocks the send if it is missing.
Group and list suppression model
Mailrelay organizes contacts into Groups (equivalent to lists in other platforms). An unsubscribe click removes the contact from the specific Group associated with the campaign, preserving membership in other Groups. Account settings can enforce account-wide suppression, which removes the address from every Group simultaneously and adds it to a permanent blocklist. This is the safer default for single-brand senders. Mailrelay also exposes an API endpoint for programmatic suppression management and CRM synchronization.
RFC 8058 one-click headers
Mailrelay 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 Account > Sending Domains. SPF and DKIM records must be verified. The free-tier limit (80,000 emails/month) includes RFC 8058 headers automatically, so smaller senders on the free plan meet the modern bulk-sender requirements without upgrading.
GDPR compliance and European positioning
As a Spanish platform serving the European market heavily, Mailrelay defaults to GDPR-oriented behavior: double opt-in available at the Group level, timestamped consent records per contact, and permanent suppression on opt-out that cannot be overridden through the API. Reactivation requires the subscriber to re-opt in through a Mailrelay signup form, which triggers a fresh double opt-in confirmation. Data residency is EU-based by default, an important point for European businesses subject to strict data protection requirements.
Frequently Asked Questions
What is the Mailrelay unsubscribe tag?
The tag is {{unsubscribe_url}}. Mailrelay replaces it at send time with a signed URL unique per subscriber. Use it inside an anchor: <a href="{{unsubscribe_url}}">Unsubscribe</a>.
Does the Mailrelay free tier include one-click unsubscribe?
Yes. The free tier (up to 80,000 emails/month for verified senders) includes automatic List-Unsubscribe and List-Unsubscribe-Post header injection on authenticated domains, satisfying the Google and Yahoo bulk-sender requirements without an upgrade.
Why does Mailrelay refuse to save my campaign?
Mailrelay enforces unsubscribe tag presence at save time. If the campaign lacks {{unsubscribe_url}} anywhere in the body, the editor blocks the save. Add the tag inside a footer text block or a legally compliant anchor.
Can I resubscribe a contact who unsubscribed from Mailrelay?
No, not through the API. Mailrelay enforces permanent suppression on opt-outs. The subscriber must re-opt in through a Mailrelay signup form, which triggers a fresh double opt-in confirmation email.
Where does Mailrelay store subscriber data?
In EU data centers by default, matching GDPR data residency expectations for European businesses. Mailrelay is headquartered in Spain and processes all subscriber data within the EU. This is a notable difference from US-focused platforms where data may traverse multiple jurisdictions.
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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