Topics

Topics are subscription categories — "Product updates", "Newsletter", "Promotions" — that give recipients finer control than a single global unsubscribe.

Each topic has a default_subscription of opt_in or opt_out, fixed at creation:

• opt_in — every contact is subscribed unless they opt out.
• opt_out — contacts are only included after they explicitly opt in.

How topics apply

• Broadcasts can target a topic. The fan-out includes only contacts whose effective subscription for that topic is "subscribed" (their explicit choice if they made one, the topic default otherwise), and always excludes globally unsubscribed contacts.
• The hosted unsubscribe page lists the team's public topics, so a recipient can opt out of one category while staying subscribed to the rest — or unsubscribe from all marketing email. Transactional sends without a topic_id are unaffected by either choice. The page speaks fourteen languages, picked from the recipient's browser (Accept-Language), English when none matches; Settings → Unsubscribe page previews each one.

API

POST/GET/DELETE /topics and GET /topics/{id} manage topics; a contact's choices are written with PATCH /contacts/{id}/topics, passing a bare array of entries like { "id": "<topic-id>", "subscription": "opt_in" }, and read back with GET /contacts/{id}/topics, which lists every topic with the contact's effective subscription and an explicit flag (false when it is the topic's default). A send with a topic_id whose every to recipient is opted out is refused with 422 all_recipients_suppressed. See the API reference.