Unsubscribes & Suppressions

eSMS Mail helps you honor opt-outs automatically and keep sending to people who actually want your email — which is what keeps you out of spam folders.

The suppression list

The suppression list is the set of addresses eSMS Mail will not send to. When you send to a suppressed address, the email is dropped before delivery and recorded so you can see it in your logs.

Addresses are added automatically when:

• an email hard bounces (the mailbox doesn't exist / permanently rejects),
• a recipient files a spam complaint (via provider feedback loops),
• a recipient clicks unsubscribe.

You can also manage the list yourself — on the Suppressions page of the dashboard, or via the API.

# List suppressed addresses
curl https://send.esmsafrica.io/v1/suppressions \
  -H "Authorization: Bearer esms_k_your_api_key"

# Manually suppress an address
curl -X POST https://send.esmsafrica.io/v1/suppressions \
  -H "Authorization: Bearer esms_k_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"email_address": "someone@example.com"}'

# Remove an address (re-enable sending to it)
curl -X DELETE https://send.esmsafrica.io/v1/suppressions/{id} \
  -H "Authorization: Bearer esms_k_your_api_key"

Each entry has a reason — bounce, complaint, unsubscribe, or manual. Adding or removing entries requires the manage scope.

One-click unsubscribe (RFC 8058)

Bulk senders are expected by Gmail and Yahoo to support one-click unsubscribe. eSMS Mail adds the required headers to every message automatically:

List-Unsubscribe: <https://send.esmsafrica.io/t/u/TOKEN>, <mailto:unsubscribe@…>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

Mailbox providers render an Unsubscribe link next to the sender name. When the recipient clicks it, the provider POSTs to the HTTPS URL, eSMS Mail adds that recipient to your suppression list (reason unsubscribe), and they stop receiving your mail — no landing page, no login. This is on by default; you don't have to build anything.

Add your own unsubscribe link

For newsletters, also include a visible unsubscribe link in the body. Point it at the same token URL that appears in the header, or at your own preference center that calls the suppression API. Every marketing email should give recipients an obvious way out — it's both good practice and a deliverability requirement.

Why this matters

Providers watch your complaint rate and bounce rate. Sending to addresses that bounce or that already opted out drives both up and gets your future mail throttled or junked. Letting eSMS Mail suppress automatically keeps those rates low and your delivery high. See Deliverability for DNS setup (SPF, DKIM, DMARC) that complements this.