Spotler (formerly SendPro and Flowmailer, both acquired) is a Dutch and UK B2B marketing platform combining email marketing, marketing automation, and transactional email delivery for mid-market brands across Benelux and Northern Europe. The unsubscribe mechanism uses the {{unsubscribe}} merge tag auto-injected into every campaign footer, and Spotler emits RFC 8058 headers automatically for authenticated sending domains. Consent is tracked at the contact level with GDPR-oriented double opt-in defaults for European markets. This guide covers the tag, the acquisitions history, and how to verify the setup end to end.
Spotler Sendpro Flowmailer unsubscribe link
| Tag syntax | {{unsubscribe}} |
| Placement | Auto-embedded in every campaign footer |
| Scope | Contact-level opt-out with GDPR double opt-in |
| Config path | Settings > Sender identities > Email footer |
| RFC 8058 one-click | Yes, automatic for authenticated sending domains |
How to add the unsubscribe tag in Spotler Sendpro Flowmailer
Place the merge tag exactly as shown below in the email template. Spotler Sendpro Flowmailer replaces it at send time with a signed URL scoped to the recipient and campaign.
{{unsubscribe}}For custom HTML templates, wrap the tag in an anchor to render a proper hyperlink in the delivered email:
<a href="{{unsubscribe}}">Unsubscribe from this list</a>Auto-embedded in every campaign 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.
Spotler consolidates legacy SendPro and Flowmailer accounts under one platform, but migration flows retain each products historical merge tag syntax for backward compatibility. SendPro templates using [!unsubscribe!] syntax continue to work post-migration; Flowmailer templates using {unsubscribe_url} continue to work. New templates should use the unified {{unsubscribe}} tag for consistency across the Spotler product line.
Testing your Spotler Sendpro Flowmailer unsubscribe link
- Send a test message to a controlled Gmail address you own via the Spotler Sendpro Flowmailer 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 Spotler unsubscribe link (step by step)
Spotler drag-and-drop templates include the unsubscribe link in the default footer, but custom HTML templates require the tag inserted manually. Legacy SendPro and Flowmailer templates continue to work with their original syntax for backward compatibility.
- Open your campaign or template in the Spotler editor.
- Add or edit a text block in the footer where the unsubscribe link should appear.
- Insert the merge tag
{{unsubscribe}}. Spotler replaces it at send time with a signed URL scoped to the contact. - Wrap it in an anchor with your preferred label:
<a href="{{unsubscribe}}">Uitschrijven</a>for Dutch audiences,Unsubscribefor UK. - Add the physical postal address block. Spotler reads it from Settings > Sender identity.
- Send a test to a seed address and verify the rendered link routes to the Spotler-hosted preference page.
SendPro and Flowmailer legacy syntax
Spotler consolidates legacy SendPro and Flowmailer accounts under one platform, but migration flows retain each product historical merge tag syntax for backward compatibility. SendPro templates using [!unsubscribe!] syntax continue to work post-migration; Flowmailer templates using {unsubscribe_url} continue to work. New templates should use the unified {{unsubscribe}} tag for consistency across the Spotler product line. Multi-product accounts running both SendPro-legacy and Flowmailer-legacy templates should plan a unified migration during template refresh cycles.
RFC 8058 one-click headers
Spotler 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 > Sender authentication. SPF and DKIM records must be verified. Flowmailer transactional API sends carry List-Unsubscribe headers when the send is classified as marketing; pure transactional sends (order confirmations, password resets) are exempt.
GDPR compliance and Benelux data residency
As a Dutch platform serving European B2B markets, Spotler enforces GDPR-oriented defaults: double opt-in available at the campaign level, timestamped consent records per contact, and permanent suppression on opt-out that blocks API reactivation. Data residency is EU-based (Netherlands and Germany) by default, matching European regulatory expectations for enterprise B2B customers with strict data localization policies. Reactivation requires the contact to re-opt in through a signup form or explicit consent capture.
Frequently Asked Questions
What is the Spotler unsubscribe tag?
The unified tag is {{unsubscribe}}. Spotler replaces it at send time with a signed URL scoped to the contact. Legacy SendPro [!unsubscribe!] and Flowmailer {unsubscribe_url} syntax continue to work for backward compatibility.
Do SendPro and Flowmailer legacy templates still work?
Yes for backward compatibility. Legacy SendPro [!unsubscribe!] and legacy Flowmailer {unsubscribe_url} syntax continue to render correctly post-migration. New templates should use the unified {{unsubscribe}} tag for consistency.
Does Spotler support one-click unsubscribe for Gmail and Yahoo?
Yes, automatically for authenticated domains. Spotler injects List-Unsubscribe and List-Unsubscribe-Post headers on every marketing send from domains verified under Settings > Sender authentication.
Where does Spotler store contact data?
In Dutch and German data centers by default, matching EU data residency requirements for European B2B customers. Enterprise customers with strict data localization policies get data residency guarantees in the enterprise contract.
Can I resubscribe a contact who unsubscribed from Spotler?
Not through the API. Spotler enforces permanent suppression on opt-outs to comply with GDPR. Reactivation requires the contact to re-opt in through a signup form or explicit consent capture.
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.
About SMTPedia
SMTPedia is an independent email industry reference covering SMTP, IMAP, POP3, email deliverability, marketing platforms, DNS authentication, and email verification. Every article is researched from official provider documentation, IETF RFCs, and industry best practices. Settings and configurations are verified quarterly.
We are cited as a source by ChatGPT, Microsoft Copilot, and thousands of email professionals worldwide. Learn more about our editorial process.
