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Suppression list

Anyone who shouldn't receive stays protected.

Addresses with a permanent bounce, or that marked the email as spam, go onto a protection list on their own. Postal removes those addresses from every send, so your reputation doesn't pay the price.

  • Added automatically
  • Applies to the API, SMTP, campaigns and automations
  • Up to 100 addresses per request

How it works

Goes in, protects and comes out whenever you want

Where addresses come from

Added to the list automatically

When an email has a permanent bounce or the person marks it as spam, Postal puts the address on your team's suppression list. You can also add anyone you want.

On every send

Left out of every send

The list applies to everything your team sends: system emails, campaigns and automations. Anyone on it is removed from the send and Postal logs the event, so you can see what happened.

See how delivery works
Control

View, add and remove whenever you need

The list lives in the dashboard, under Suppressions, with the source and date of each address. To add, type the email. To remove, one click. Remove only when you're sure, for example after the person has corrected the address.

See the suppressions API
API

Bring in the list from another tool

Through the API, up to 100 addresses per request. Every address that enters or leaves the list generates a webhook event.

POST /suppressions/batch/add
{
  "emails": [
    "[email protected]",
    "[email protected]"
  ]
}
201Up to 100 per request

With and without the list

Without the suppression list

  • An address that doesn't exist keeps getting send attempts
  • Anyone who marked the email as spam can receive it again
  • Every repeated send weighs on your team's bounce and complaint rates

With the suppression list

  • The address is left out of the next send, on the API, SMTP, campaigns and automations
  • Postal logs the email.suppressed event, so you can see what happened
  • You check, add and remove addresses in the dashboard or through the API

Before you send

Validation helps clean the list, and unsubscribing is a separate matter.

Validation

Validate the list before sending

Email validation checks each address before sending and cross-references the result with your history: anyone who already marked an email of yours as spam or is on the suppression list shows up as invalid, with the reason next to it.

Learn about email validation
  • Checks syntax, domain and, when the provider allows it, whether the mailbox exists
  • Works on one address, a CSV file, a segment or all contacts
  • Uses credits, which depend on the plan; an address verified in the last 90 days is free
Two lists

Unsubscribing and suppression are not the same thing

Anyone who unsubscribes from a campaign is recorded on the contact. The suppression list belongs to the team and holds permanent bounces, complaints and manual entries.

  • An address on the list never becomes a contact, not even through a form or import
  • Unsubscribes count in the campaign statistics
  • Reactivating someone who left or complained requires new consent, as the Terms of Use say

Frequently asked questions

Does every bounce put the address on the list?

Only permanent ones, when the address doesn't exist. Temporary bounces, like a full mailbox, don't put the address on the list.

Can I take an address off the list?

Yes, in the dashboard or through the API. It's useful when the person has corrected the address. Avoid removing anyone who complained or asked to leave: without new consent, that goes against the Terms of Use.

What about people who unsubscribe from a campaign?

The unsubscribe is recorded on the contact: the person stops receiving campaigns (or leaves only the topic, when the campaign was for a topic) and the exit counts in the campaign statistics. It's separate from the suppression list, which holds permanent bounces, complaints and manual entries.

Can I import the list I already have?

Yes, through the API, with up to 100 addresses per request. People migrating from another tool usually start there. See the migration guide.

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