Guide: sending
List hygiene and suppression
The addresses you stop mailing matter as much as the ones you add. A suppression list is the record of everyone who must not receive a given kind of mail from you again.
Last reviewed November 4, 2026
Start with consent
Mail people only for what they asked for. Marketing mail needs a clear opt-in; transactional mail, such as receipts or password resets, follows from something the recipient did. Never buy or rent lists: they contain old addresses, people who never agreed, and spam traps.
Check addresses when they are collected. A typo caught on the sign-up form never becomes a bounce.
Make leaving easy
A recipient who cannot find the unsubscribe link reports the message as spam instead, and a complaint costs far more than an unsubscribe. Put a visible link in every marketing message and add the List-Unsubscribe header with one-click support (RFC 8058), which lets mail clients show their own unsubscribe button. One-click works only when the HTTPS address accepts the POST request and a DKIM signature covers both headers.
Google and Yahoo require one-click unsubscribe for marketing and subscribed mail from bulk senders. Yahoo asks that unsubscribes be honoured within 2 days, and Google within 48 hours.
List-Unsubscribe: <https://example.com/u/abc123>
List-Unsubscribe-Post: List-Unsubscribe=One-ClickWho to suppress
- Hard bounces: the address does not exist. Suppress permanently.
- Spam complaints: the recipient told their provider the mail is unwanted. Stop mailing them.
- Unsubscribes: stop the kind of mail they left, for example one newsletter or all marketing, but keep sending the receipts and account mail they still need.
- Role addresses such as info@ or admin@ reach several people or none; send marketing to them only if someone asked for it.
Inactive recipients and spam traps
Abandoned mailboxes can be turned into spam traps by providers, and mail to them hurts your reputation without warning. Define a period after which a recipient who never engages gets a re-engagement message, and stop mailing those who still do not respond.
Keep complaints low. Google and Yahoo ask senders to keep the spam rate shown in their tools below 0.3%, and Google recommends staying below 0.1%.
Keep the list when you change provider
Export your suppression list from the old provider, with its bounces, complaints and unsubscribes, and import it before the first send from the new one. Starting without it means mailing again the people who already left, which is both a legal and a deliverability problem.
How Mail.Land handles suppression
Mail.Land suppresses hard bounces and spam complaints for all mail automatically. An unsubscribe from marketing mail or from one list leaves transactional mail going out. Marketing messages carry List-Unsubscribe with one-click support (RFC 8058). Suppressed recipients are refused at send time and reported in the response.
You can import a suppression list from the dashboard or the API, with the types HardBounce, Complaint, Unsubscribe and Manual, before your first campaign; entries already present for the same scope and list are skipped. The validation API checks syntax, likely typos, disposable and role addresses and the domain's mail servers, with an optional mailbox check once your account is approved.
Sources
- RFC 8058, Signaling One-Click Functionality for List Email Headers (checked November 4, 2026)
- Google, Email sender guidelines (checked November 4, 2026)
- Yahoo, Sender best practices (checked November 4, 2026)
Put it into practice
Add your domain to Mail.Land and the dashboard shows the exact SPF, DKIM and DMARC records to publish.