Channels & Targeting

Channels

Channel	Handler	OneSignal semantics
`push`	`handleNotificationPush`	`POST /notifications` with `contents`/`headings` + `target_channel: push`.
`in_app`	`handleNotificationInApp`	Data-only push (`content_available`, no `contents`).
`sms`	`handleNotificationSms`	`POST /notifications` with `target_channel: sms` + E.164 phone.
`live_activity`	`handleNotificationLiveActivity`	Live Activity `start` / `update` based on `data.action`.

Categories and suppression

Category	Opt-out?
`marketing`	Yes (suppressible)
`transactional`	No
`payment`	No
`system`	No

NON_SUPPRESSIBLE_CATEGORIES = ["payment", "system", "transactional"]. Users can never mute these categories; gating only applies to suppressible ones (currently marketing).

Targeting

Push / in-app / live activity

Targeted by include_aliases.external_id = [auth.users.id]. The mobile SDK sets it on login.

SMS

Targeted by include_phone_numbers with the E.164 phone resolved from user_metadata.phone / user_phone.

horizon-api holds no device tokens. The mobile SDK must call OneSignal.login(auth.users.id) so OneSignal can resolve the external_id the backend targets.

Result classification

Situation	Result
OneSignal 2xx with `id`	Processed (`context.oneSignalId`).
200 with `errors` like “no subscribed users”	Logged skip (no-op delivery).
No / invalid phone (SMS)	`NonRetryableNotificationError` → skip.
5xx / network error	Error → retry with backoff → DLQ.

Architecture Preferences & Inbox

Get Started

API Documentation

OAuth & Identity (IdP)

Monitoring & Infrastructure

Realtime (Pusher)

Notifications (OneSignal)

Channels

Categories and suppression

Targeting

Push / in-app / live activity

SMS

Result classification

​Channels

​Categories and suppression

​Targeting

Push / in-app / live activity

SMS

​Result classification

Channels

Categories and suppression

Targeting

Result classification