Unione.io is a cloud email delivery platform offering SMTP relay and API endpoints for transactional and marketing sends, popular with SaaS applications and e-commerce platforms across Eastern European and CIS markets. The unsubscribe mechanism uses the {{unsubscribe_url}} merge variable in email templates, and Unione.io supports RFC 8058 header injection via the API headers parameter or via the project-level default configuration. Suppression is tracked per project with granular scope control. This guide covers the tag, the per-project model, and how to verify the setup end to end.
Unione.io unsubscribe link
| Tag syntax | {{unsubscribe_url}} |
| Placement | Manual placement in message template |
| Scope | Per-project suppression scope |
| Config path | Dashboard > Projects > Settings > List-Unsubscribe |
| RFC 8058 one-click | Yes via API headers parameter or project-level default |
How to add the unsubscribe tag in Unione.io
Place the merge tag exactly as shown below in the email template. Unione.io 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>Manual placement in message template
Yes via API headers parameter or project-level default 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.
Unione.io projects segregate suppression pools per sending workflow (transactional, marketing, notifications). Sending marketing content through a transactional project bypasses the marketing suppression list but violates deliverability best practices. Classify projects correctly during setup and audit periodically to catch misrouted sends.
Testing your Unione.io unsubscribe link
- Send a test message to a controlled Gmail address you own via the Unione.io 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
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How to add the Unione.io unsubscribe link (step by step)
Unione.io message templates require manual placement of the unsubscribe merge variable since the platform serves developer teams building custom email templates.
- Open your Unione.io template in the dashboard or in your application template file.
- Add or edit a text block in the footer where the unsubscribe link should appear.
- Insert the merge variable
{{unsubscribe_url}}. Unione.io replaces it at send time with a signed URL scoped to the recipient and project. - Wrap it in an anchor:
<a href="{{unsubscribe_url}}">Unsubscribe</a>. - Configure the project List-Unsubscribe defaults under Dashboard > Projects > Settings > List-Unsubscribe.
- Send a test to a seed address and verify the rendered link routes to the Unione.io-hosted unsubscribe confirmation page.
Per-project suppression scope
Unione.io projects segregate suppression pools per sending workflow (transactional, marketing, notifications). Sending marketing content through a transactional project bypasses the marketing suppression list but violates deliverability best practices. Classify projects correctly during setup and audit periodically to catch misrouted sends. This is analogous to Postmark Message Streams and SocketLabs Server IDs models. SaaS applications with distinct product lines often use separate projects per product for clean suppression scope.
RFC 8058 via API or project default
Unione.io supports RFC 8058 List-Unsubscribe and List-Unsubscribe-Post header injection two ways: per-message via the API headers parameter (fine-grained control), or via the project-level default configured per project (turnkey compliance). For marketing sends, the project-level default is recommended to avoid per-message header injection code. For hybrid transactional-marketing sends, the API headers parameter gives per-message control based on content classification.
Eastern European and CIS market deliverability
Unione.io routes sends through infrastructure with peering to Eastern European and CIS email networks (Mail.ru, Yandex, Rambler, Ukr.net). Recipients in Russia, Ukraine, Kazakhstan, and Belarus may see better inbox placement via Unione.io than through global ESPs due to regional network peering. Complaint feedback from regional inbox providers is processed in real time and syncs to the project suppression list. Data centers in Eastern Europe match regional data residency expectations.
Frequently Asked Questions
What is the Unione.io unsubscribe tag?
The merge variable is {{unsubscribe_url}}. Unione.io replaces it at send time with a signed URL scoped to the recipient and project. Use it inside an anchor: <a href="{{unsubscribe_url}}">Unsubscribe</a>.
What is a Unione.io project?
Projects segregate suppression pools per sending workflow (transactional, marketing, notifications). This is analogous to Postmark Message Streams and SocketLabs Server IDs. Classify projects correctly to prevent marketing content from bypassing suppression via transactional projects.
Does Unione.io support one-click unsubscribe for Gmail and Yahoo?
Yes via two paths: per-message API headers parameter for fine-grained control, or project-level default for turnkey compliance. Both inject List-Unsubscribe and List-Unsubscribe-Post headers on authenticated sending domains.
Is Unione.io optimized for Eastern European inbox providers?
Yes. Unione.io routes through infrastructure with peering to Mail.ru, Yandex, Rambler, Ukr.net, and other regional email networks. Recipients in Russia, Ukraine, Kazakhstan, and Belarus often see better inbox placement than through global ESPs.
Where does Unione.io store suppression data?
In Eastern European data centers matching regional data residency expectations. Enterprise customers with specific data localization requirements should discuss regional data center options with Unione.io support during account setup.
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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