Topics

Topics model subscription preferences by subject (“product updates”, “weekly digest”, “security notices”) so recipients can opt out of one kind of mail without leaving your list.

curl https://api.sendsignal.dev/topics \
  -H "Authorization: Bearer ss_..." -H "Content-Type: application/json" \
  -d '{"name": "Weekly digest", "description": "Monday roundup", "default_subscription": "opt_in"}'

default_subscription controls contacts who have never expressed a preference:

• opt_in (default): only contacts who explicitly subscribed receive topic broadcasts.
• opt_out: everyone receives them unless they explicitly unsubscribed.

Subscriptions

Set a contact’s preference with PUT /contacts/{id}/topics/{topicId} and {"subscribed": true} or {"subscribed": false}; read them with GET /contacts/{id}/topics.

Recipients manage this themselves too: when a send is tagged with a topic_id, its unsubscribe link unsubscribes from that topic only.

Targeting

A broadcast with a topic_id mails the topic’s effective subscribers (explicit preference, falling back to the default), minus unsubscribed or suppressed contacts.

GET /topics, GET /topics/{id}, and DELETE /topics/{id} round out management.