Domains & deliverability
One-click unsubscribe
Every marketing email Deckle sends carries the headers and visible link that let recipients unsubscribe in a single click — and unsubscribing suppresses the contact automatically.
Bulk senders are now required to support one-click unsubscribe. Deckle handles this for you: marketing and broadcast sends ship with the right headers and a visible unsubscribe link, and the click flows through to a hosted preference page that suppresses the contact.
Why it's required#
Gmail and Yahoo's bulk-sender rules require that any sender delivering large volumes of mail supports one-click unsubscribe. A recipient must be able to opt out with a single action, without logging in or filling out a form, and you must honor that request promptly.
Alongside one-click unsubscribe, the same rules require authenticated mail (SPF, DKIM, and DMARC) and a low spam-complaint rate. Getting unsubscribe wrong hurts your deliverability directly — mailbox providers treat “this is spam” clicks as a much stronger negative signal than a clean unsubscribe. Making it easy to leave keeps your reputation healthy.
This applies to marketing mail
One-click unsubscribe is added to marketing and broadcast sends — campaigns, automations, and newsletters. Purely transactional messages (receipts, password resets) are not treated as bulk marketing and are out of scope for the requirement.What Deckle adds#
When you send a campaign or a marketing automation, Deckle automatically attaches two headers and injects a visible unsubscribe link into the email. You don't configure anything — it rides on every eligible send from your verified domain.
The headers#
Deckle sets both the List-Unsubscribe header and the List-Unsubscribe-Post header. Together they tell Gmail and Yahoo that the message supports RFC 8058 one-click unsubscribe, which is what surfaces the native “Unsubscribe” control next to the sender name in the inbox.
List-Unsubscribe: <https://app.getdeckle.com/u/unsub_9f3c...>
List-Unsubscribe-Post: List-Unsubscribe=One-ClickThe List-Unsubscribe-Post: List-Unsubscribe=One-Click line is the piece that makes it a true one-click: the mailbox provider sends a single POST to the unsubscribe URL on the recipient's behalf, with no confirmation step, and Deckle records the opt-out.
The visible link#
Header-based unsubscribe only works in clients that support it. So Deckle also injects a visible unsubscribe link into the body of every marketing and broadcast email — typically in the footer, next to your sending address. This is a hard requirement of the bulk-sender rules, and it guarantees a working opt-out for every recipient regardless of their mail client.
Templates from the gallery
Templates in the gallery already include a footer with the unsubscribe link and your brand details. When you send them as part of a campaign or automation, the link is populated automatically — see the template gallery.The preference page#
Both the header URL and the visible link point at a hosted preference page that Deckle runs for you. There's nothing to build or host yourself. When a recipient lands there, they can confirm their unsubscribe, and the page reflects the outcome back to them.
Recipient clicks unsubscribe
Deckle records the opt-out
Future marketing sends skip them
Unsubscribing suppresses the contact#
An unsubscribe isn't just a flag on a contact — it adds the address to your suppression list with the reason unsubscribe. Suppression is enforced platform-wide: any attempt to send to a suppressed address is rejected with a 422, so an unsubscribed contact can't be re-emailed by accident.
The unsubscribe reason sits alongside the other ways an address lands on the suppression list.
| Reason | How it's added |
|---|---|
unsubscribe | Recipient used one-click unsubscribe or the hosted preference page. |
hard_bounce | SES reported a permanent bounce; added automatically. |
complaint | Recipient marked the message as spam; added automatically. |
manual | You added the address by hand in the dashboard or via the API. |
If someone unsubscribes by mistake and asks to be re-added, you can remove them from the suppression list — in the dashboard, or with deckle.suppressions.delete(email). Only do this with the contact's explicit consent; re-emailing an address that opted out is the fastest way to earn spam complaints.
Keep complaints low
A frictionless unsubscribe is your best defense against complaints. Aim to keep your complaint rate under 0.3% — the dashboard warns you as you approach the threshold. The deliverability guide covers the full checklist.