> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sendrealm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Topics

> Manage reusable audience preference topics and subscription actions.

Topics are reusable subscription groups that let you manage preferences separately from audiences.

## Use topics when

* A contact can opt in or out without leaving an audience
* You want automations to subscribe or unsubscribe users from a preference
* You need a stable API resource for notification categories

## Common examples

* `product-updates`
* `weekly-digest`
* `shipping-alerts`

## Subscribe a contact

```bash theme={null}
curl https://api.sendrealm.com/contacts/c671f89b-3ec1-4c58-9ad2-4ef8c2917cda/topics/8c3c4d0e-f7f3-4d7f-92ae-b1498f6a2fa9 \
  -X PUT \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "is_subscribed": true
  }'
```

## Related pages

* [Topics API](/api-reference/endpoint/topics)
* [Contact Topic Subscription API](/api-reference/endpoint/contact-topic-subscription)