Overloop (formerly Prospect.io) is a sales engagement platform combining cold email, LinkedIn automation, and CRM tracking for outbound sales teams. The unsubscribe mechanism uses the {{unsubscribe_link}} merge variable placed manually in the email body, with automatic reply-based opt-out detection. Overloop tracks opt-outs at the workspace level with CRM sync options. RFC 8058 compliance depends on the sending mailbox authentication. This guide covers the tag, the Prospect.io legacy compatibility model, and how to verify the setup end to end.
Overloop unsubscribe link
| Tag syntax | {{unsubscribe_link}} |
| Placement | Manual placement in the email body |
| Scope | Workspace-wide opt-out with CRM sync |
| Config path | Settings > Unsubscribes > Configuration |
| RFC 8058 one-click | Depends on connected mailbox (Google Workspace, Microsoft 365) authentication |
How to add the unsubscribe tag in Overloop
Place the merge tag exactly as shown below in the email template. Overloop 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>Manual placement in the email body
Depends on connected mailbox (Google Workspace, Microsoft 365) authentication 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.
Overloop rebranded from Prospect.io retains the previous product template syntax for backward compatibility, but new templates should use the current merge variable format. Legacy Prospect.io templates using older merge patterns continue to work but should be migrated during template refresh cycles to align with current documentation.
Testing your Overloop unsubscribe link
- Send a test message to a controlled Gmail address you own via the Overloop 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 Overloop unsubscribe link (step by step)
Overloop cold outreach templates require the unsubscribe merge variable inserted manually in the email body. There is no auto-injected footer since cold outreach templates aim for personal-feel formatting.
- Open your sequence or template in the Overloop editor.
- Add the merge variable
{{unsubscribe_link}}at the end of the email body, typically after your signature. - Wrap it in an anchor:
<a href="{{unsubscribe_link}}">Unsubscribe</a>. - Configure workspace-level unsubscribe handling under Settings > Unsubscribes > Configuration.
- Enable CRM sync so opt-out state writes back to the CRM contact record.
- Send a test through each connected mailbox and verify the rendered link routes to the Overloop-hosted preference page.
Prospect.io template migration
Overloop rebranded from Prospect.io retains the previous product template syntax for backward compatibility, but new templates should use the current merge variable format. Legacy Prospect.io templates using older merge patterns continue to work but should be migrated during template refresh cycles to align with current documentation. When creating new sequences, standardize on the current syntax to avoid team confusion when template authors reference documentation. Existing Prospect.io template libraries can be imported and continue functioning without immediate migration.
RFC 8058 one-click headers
Overloop RFC 8058 compliance depends on the sending mailbox authentication. Google Workspace and Microsoft 365 mailboxes with proper SPF, DKIM, and DMARC alignment inherit RFC 8058 headers on Overloop-sent messages. Unauthenticated mailboxes fall out of one-click compliance regardless of Overloop UI settings. Audit connected mailboxes before enabling high-volume outreach. This is the standard cold outreach compliance pattern shared with Reply.io, Lemlist, Smartlead, and Instantly.
Sales engagement CRM sync and opt-out flow
Overloop sales engagement CRM integrations write opt-out state back to the CRM contact record when an outreach recipient unsubscribes or replies with an opt-out keyword. Configure bidirectional sync so a CRM-side opt-out also suppresses further Overloop sends, preventing outreach from manual CRM-triggered emails to unsubscribed prospects. LinkedIn outreach opt-outs (a connect request rejection or explicit stop message) can also be configured to flow into the workspace suppression list.
Frequently Asked Questions
What is the Overloop unsubscribe tag?
The merge variable is {{unsubscribe_link}}. Overloop replaces it at send time with a workspace-scoped signed URL. Place it manually in the email body since cold outreach templates typically avoid auto-injected footers.
Do Prospect.io legacy templates still work in Overloop?
Yes. Overloop retains backward compatibility with Prospect.io template syntax. New templates should use the current merge variable format, but legacy templates continue functioning without immediate migration.
Does Overloop support one-click unsubscribe for Gmail and Yahoo?
Depends on the sending mailbox authentication. Google Workspace and Microsoft 365 mailboxes with proper SPF, DKIM, and DMARC alignment inherit RFC 8058 headers. Unauthenticated mailboxes fall out of one-click compliance regardless of Overloop UI settings.
Does Overloop detect reply-based opt-outs?
Yes. Overloop scans incoming replies for unsubscribe phrases and auto-suppresses the contact. Configure keyword sensitivity carefully to avoid false positives on ambiguous natural-language phrasing.
Do LinkedIn outreach opt-outs sync to Overloop email suppression?
Yes when configured. LinkedIn opt-outs (a connect request rejection or explicit stop message) can flow into the workspace-wide suppression list, ensuring cross-channel consistency for the same prospect.
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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