Unsubscribe and suppression

Every campaign email gives its recipient a way to stop hearing from you, and every opt-out is honoured automatically across the whole workspace. This page covers the three mechanisms, the suppression list behind them, and the settings that shape what a recipient sees.

What a recipient sees

Warmbly appends an opt-out to every campaign email, after the signature. There are three modes, set for the workspace under Settings > Sending > Unsubscribe and overridable per campaign under Preferences:

The wording of the sentence and of the link text is yours to change.

Reply to opt out is the default because it reads as a personal email, which is what cold outreach is. A formal unsubscribe link and footer are the strongest signal a mailbox provider has that a message is bulk marketing, and several deliverability teams report worse placement for cold email that carries one. A reply that asks to stop is detected and honoured automatically (see below), so the plain sentence is a real mechanism, not a courtesy. CAN-SPAM, CASL and the Australian Spam Act all accept a reply as the opt-out method.

Unsubscribe link is the right choice when your list skews toward consumers, when your legal team asks for a link, or when your volume is high enough that provider bulk-sender rules apply. The link is unique to the recipient and campaign, signed so it cannot be guessed or altered, and valid for a year after the send. Clicking it opens a plain confirmation page with one button. Nothing happens until the button is pressed, because link scanners and preview fetchers follow every link in an email. The page then offers a way back for anyone who unsubscribed by mistake.

You can also place the link inside your own copy instead of the footer: insert the Unsubscribe link variable from the variable menu, or type {{.UnsubscribeLink}}. Click tracking never rewrites it, so an opt-out is never counted as a click.

The List-Unsubscribe header

Independently of the body, each campaign can attach the List-Unsubscribe and List-Unsubscribe-Post headers (RFC 8058). Mail clients that recognise them show their own Unsubscribe control next to the sender's name, and pressing it opts the recipient out with no page at all. The toggle is Preferences > Unsubscribe header, on by default.

Two things to know. Gmail only shows its button for mail it already classes as bulk, so a one-to-one style cold email from a Workspace mailbox usually does not get one. And Google and Yahoo require the header only above roughly five thousand messages a day to their consumer inboxes, which no mailbox at Warmbly's default limits approaches. The header costs nothing and is worth leaving on; it is not a substitute for the opt-out line.

Replies that ask to stop

Warmbly reads every reply to a campaign email. One that asks to stop, in wording such as "unsubscribe", "remove me", "stop emailing me", "opt out" or "do not contact", puts the sender on the suppression list immediately. Only the new text of the reply is read: the quoted history below it carries your own opt-out wording and is ignored. Phrases match on whole words, so "stop by our booth" does not opt anyone out.

A reply that says "not interested" is classed as negative and can stop the sequence, but it does not suppress the contact. Someone who says no today may be a fit next year; someone who says stop is asking not to be contacted at all.

Turn this off with Settings > Sending > Honour replies that ask to stop if you would rather handle such replies by hand. Leaving it off with the reply-to-opt-out line in place means promising an opt-out you then honour manually.

The suppression list

Contacts > Suppression list is every address and domain that no campaign in the workspace will email, however it got there:

The list is workspace-wide. An entry stops the address in every campaign, in new campaigns created later, and in the unibox composer, which refuses to send to it. Import a list containing a suppressed address and the contact is created but never mailed. The launch check counts suppressed leads out of a campaign's deliverable total, so what the campaign says it will send is what it sends.

Adding entries. Press Add and paste addresses or domains, one per line or as a column from a spreadsheet. A bare domain (acme.com or @acme.com) suppresses every address at it, which is the usual way to keep customers, partners and your own company out of outreach. An optional reason is kept with each entry.

Removing entries. Each entry has a Remove action, and a suppressed contact's drawer shows the same. Removing an entry the recipient made themselves, by unsubscribing, complaining or bouncing, is confirmed with a stronger warning and recorded in the audit log with who lifted it and why the address was listed. Removing an address also restores the contact's Subscribed flag, so the two never disagree.

Contacts and the Subscribed flag. The contact's own Subscribed toggle is a second gate: a contact switched off is skipped by every campaign even with no suppression entry. An opt-out sets both, so a contact who unsubscribed reads as unsubscribed everywhere.

Suppression entries travel with a workspace export, so a workspace moved to another instance does not re-mail people who already opted out.

Webhooks and the API

An opt-out fires the campaign.unsubscribed webhook with a source of one_click (the mail client's button), link (the link in the email), reply (a reply asking to stop) or action (a sequence's Unsubscribe step).

The suppression list is available over the API as GET /suppressions, POST /suppressions and DELETE /suppressions/:id. See deliverability and ops.

Self-hosting

Unsubscribe links are served by the API process on the origin in API_PUBLIC_URL, so that variable must be set to the address recipients can reach. Without it Warmbly cannot mint links: the header is left off, and the link mode falls back to the reply-to-opt-out sentence. Links are signed under AUTH_SECRET; rotating it invalidates links in emails already sent.