Suppression list

The suppression list prevents Signal from delivering to addresses that should not receive mail. A suppressed address can still have a contact profile, but send attempts resolve to a suppressed outcome instead of provider delivery.

Reasons

Reason	Typical source
Bounce	A permanent delivery failure
Complaint	A spam or abuse complaint
Unsubscribe	A recipient preference action
Manual	An operator, import, or application decision

Add an address

Use Add suppression for a deliberate block. Choose the reason that accurately reflects why delivery must stop. Do not label a complaint or unsubscribe as manual just to simplify reporting.

Import

Use one entry per line. A line may contain only the email address or email,reason. Unknown or omitted reasons are treated as manual.

bounced@example.com,bounce
complained@example.com,complaint
manual-block@example.com

Validate the file before a large import:

Normalize whitespace without changing the address meaning.
Use only supported reason values.
Remove headers unless the importer explicitly accepts them.
Review the target project before submitting.

Export

Export when you need a customer-support review, provider migration, compliance workflow, or backup of delivery blocks. Protect the export as customer data.

Remove a suppression

Removal allows future eligible messages to reach provider delivery again. It does not automatically send anything that was previously blocked. Before removal, establish:

Why the entry exists.
Whether the address is now valid.
Whether the recipient has current consent.
Whether the original bounce or complaint risk is resolved.

Never bulk-remove complaint, bounce, or unsubscribe entries merely to increase sendable audience size. That damages recipient trust and sending reputation.

SDK example

After creating an authenticated client with the matching SDK setup guide, use the operation for your language or framework.

TypeScript

const suppressions = await signal.suppressions.listSuppressions(projectId, {
  headers: { Authorization: `Bearer ${process.env.SIGNAL_API_KEY}` },
});

var api = client.suppressions();
var result = try api.listSuppressions(project_id, .{});
defer result.deinit();

switch (result) {
    .success => |_| {},
    .api_error => return error.SignalApiError,
}

Getting started

Dashboard

Emails

Contacts and consent

Insights

Domains

Webhooks

Settings

Migration

Reasons

Add an address

Import

Export

Remove a suppression

SDK example

​Reasons

​Add an address

​Import

​Export

​Remove a suppression

​SDK example

Reasons

Add an address

Import

Export

Remove a suppression

SDK example