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

# Channel Fallback

> When configuring channels for an Event, the default option shows the channels to which the notifications will go first

You can also decide what happens when a notification fails to deliver on a channel. Select the "More Options" to enable
channel fallback. You can then click on the arrow icon beside a channel to
configure the fallback conditions.

### When to fallback to another channel

There can various reasons for which you can set up a fallback:

1. Provider API fails with 4xx, 5xx or times out.
2. Provider was not able to deliver the notification within X seconds.
3. Recipient details unavailable or User has opted-out of the channel

Raven allows you to add any of these conditions easily without writing any code.
Let's check each of these case by case:

**Case 1: Provider API failure**

<img src="https://mintcdn.com/raven/kmn_wV2dGv3NIOgZ/images/add-fallback.png?fit=max&auto=format&n=kmn_wV2dGv3NIOgZ&q=85&s=6c1b0415a309fb74690a6cf211272e78" alt="Provider API Failure" width="1196" height="480" data-path="images/add-fallback.png" />

This example says that: If the provider API fails (4xx, 5xx) or connection times
out within 30s, then fallback to WhatsApp. The fallback channel is triggered as
soon as the API fails. Raven waits for 30s only if there is a delay in API
success/failure response.

Note that, an API success from the provider *DOES NOT* guarantee a successful
delivery of the notification (SMS, Push, Email, WhatsApp, Voice). It means that
the provider has accepted the request and will now attempt to deliver. If you
want to fallback when the notification has not delivered instead, then check out
condition below.

**Case 2: Notification not delivered**

<img src="https://mintcdn.com/raven/kmn_wV2dGv3NIOgZ/images/add-fallback2.png?fit=max&auto=format&n=kmn_wV2dGv3NIOgZ&q=85&s=69a140f92c80e13eb441549d4ce88d78" alt="Notification Not Delivered" width="1196" height="470" data-path="images/add-fallback2.png" />

This example says that: If the notification does not deliver within 10s, then
fallback to WhatsApp. This rule is a super set of Case 1 and considers both
options:

1. API failure
2. Delivery failure (can happen due to unavailability of recipient, network
   issue etc)

Raven will trigger the fallback immediately if the provider API fails and if the
API is successful, will wait for 10s to deliver the notification. Raven waits
for the delivery report from the provider and decides based on the type of
callback received. If a callback is received which does not confirm the delivery
of the notification, the fallback will be triggered.

**Case 3: Recipient unavailable or User opted-out**

Currently, fallback by default gets triggered if the recipient details are not
present (like mobile number is empty) or if the user has opted out from the
channel. You can
[manage the user details and channel preferences](/platform/users) on Raven or
pass it in the Send Event API.

<Note>
  In case the provider is throttling requests due to some rate-limit set for
  your account, Raven will retry the request automatically till there is a
  resolution. You need not setup fallbacks in this case.
</Note>