Connect by JBRH Open Connect

One-click unsubscribe

One-click unsubscribe is a pair of headers that let a mail client show its own unsubscribe control and act on it with a single POST — no landing page, no login, no confirmation step. The largest mailbox providers require it of bulk senders. Connect enforces the honouring side; adding the header to a message is the sending mailbox's business, not something these sources document Connect doing.

Status
Reference What this means
Audience
both
Channels
email
Last verified
Product version
6.3.2

The two headers#

List-Unsubscribe: <https://example.com/u/opaque-token>, <mailto:unsub@example.com?subject=opaque-token>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

List-Unsubscribe is the older of the two and may carry a mailto: URI, an https: URI, or both. On its own it is a hint: the client may show a control, and following the link lands the person on a page where something further is expected of them.

List-Unsubscribe-Post is what makes it one click. Its presence tells the client it may send POST with the body List-Unsubscribe=One-Click to the https URI, and that doing so is sufficient. The client does this itself, from its own infrastructure, without the person's browser being involved at all.

What the obligation actually is#

Three separate pressures point at the same behaviour, and it helps to keep them apart because they apply to different senders.

Mailbox provider rules
The largest consumer providers publish bulk-sender requirements that include offering one-click unsubscribe and acting on a request within a short window measured in days. These are conditions of delivery, enforced by filtering rather than by law.
Marketing law where the recipient is
Regimes differ: some require a working opt-out mechanism in every commercial message and a deadline for honouring it; others require consent before the first message and an easy withdrawal after. Which applies depends on where the recipients are, not where the sender is.
The reputational one
A person who cannot find the unsubscribe control uses the spam button instead, which costs far more than the opt-out would have.

The third is the one that decides design arguments. Making an unsubscribe slightly harder never retains a reader; it converts an opt-out into a complaint.

Where implementations go wrong#

  1. The token is scoped to a campaign, so unsubscribing from one message leaves the person subscribed to everything else the business sends.
  2. The endpoint returns a redirect to a preference centre. A one-click POST expects to be finished; anything else means the request may not be honoured.
  3. The header is added to transactional mail, so a receipt offers to stop receipts — and someone takes it up, then does not receive the next invoice.
  4. Opt-outs are recorded in the sending tool rather than in the business's own suppression list, so changing supplier loses every one of them.
  5. The mailto: form is offered and nobody monitors the mailbox it points at.

Does Connect use one-click unsubscribe?#

Connect enforces the receiving half. Unsubscribe status sits alongside suppression, complaints and do-not-contact in the single compliance check that runs before any outreach leaves, so an address that has opted out is not contacted again by any outreach path.

The sending half — whether a particular outbound message carries List-Unsubscribe and List-Unsubscribe-Post — is a property of the message and the mailbox it goes through. Connect sends via the workspace's own Gmail, Microsoft Graph or IMAP/SMTP mailbox, and the sources behind this page do not document Connect composing those headers, so the page does not claim it. If you run bulk campaigns from a domain that also carries Connect's conversational mail, the headers are the campaign platform's responsibility.

The practical rule for a Connect workspace: if an unsubscribe reaches you anywhere — a header POST at your campaign tool, a reply saying stop, a phone call — record it as a suppression here, because that is the record the outreach gate reads.

Questions#

Does a one-click unsubscribe need a confirmation page?

No, and adding one breaks it. The client posts without a browser and expects the request to be complete; a confirmation step means the opt-out is not recorded until a human does something else, which is exactly what the mechanism was designed to remove.

Should transactional messages carry the header?

Generally not, because there is nothing to unsubscribe from — an invoice is not a subscription. The exception is a message that is arguably both, and the honest fix there is to split it rather than to offer an opt-out from something the recipient needs.

Someone replied 'stop' instead of using the link. Does that count?

Treat it as an opt-out. The mechanism exists for the sender's convenience, not as a required form of words, and a business that only honours the button will eventually explain that distinction to somebody who is not interested in it. Record it as a suppression so every later path sees it.