eSMS Mail keeps you sending to people who want your email — which is what keeps you out of spam folders. Two features do the work for you.

The suppression list

The suppression list is the set of addresses eSMS Mail will not send to. Send to a suppressed address and the email is dropped before delivery and recorded in your logs. Addresses are added automatically on a hard bounce, a spam complaint, or an unsubscribe. You can also manage it on the Suppressions page or via the API.

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

# Suppress an address manually
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"}'

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

One-click unsubscribe (RFC 8058)

Gmail and Yahoo expect bulk senders 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

Providers show an Unsubscribe link next to your sender name. When clicked, the recipient is added to your suppression list and stops receiving your mail — no landing page, no login, nothing for you to build.

Why it matters

Providers watch your complaint and bounce rates. Sending to addresses that bounce or already opted out drives both up and gets your mail throttled or junked. Automatic suppression keeps those rates low and your delivery high. Pair it with SPF, DKIM and DMARC on your domain for best results.