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

# Multi-Channel Recovery: Email, SMS, WhatsApp & In-App

> The four outreach channels Airdun can use — email, SMS, WhatsApp, in-app wall — and how the channel order is decided per case.

Airdun can reach a customer through four channels. Which ones are available depends on what you have enabled and on the contact data Stripe holds for that customer.

## Available channels

<CardGroup cols={2}>
  <Card title="Email" icon="envelope">
    Sent from your own domain via a configured sender persona. Every email includes the official Stripe invoice and a single link to update the card and settle the balance.
  </Card>

  <Card title="SMS" icon="message-sms">
    Sent from a number Airdun provisions on your behalf, local where available. Used when engagement signals suggest a more immediate channel, or as an escalation step.
  </Card>

  <Card title="WhatsApp" icon="whatsapp">
    Available for markets where WhatsApp is a primary communication channel. Airdun manages the WhatsApp Business API setup.
  </Card>

  <Card title="In-App Wall" icon="browser">
    A prompt shown inside your product at the customer's next login. Configurable as a soft reminder banner or a hard access block. Requires the Airdun snippet.
  </Card>
</CardGroup>

## How channel ordering is decided

There is no fixed sequence. The channel order is determined per case from the customer's country, prior engagement history, subscription value, product usage, and the failure type. A customer who has never opened an email may receive an SMS first; a customer in a high-WhatsApp-penetration market may receive a WhatsApp message before an email.

The full list of signals and what the strategy determines is documented in [Recovery Strategy](/how-it-works/recovery-strategy).

## Timing and language

<Note>
  All outreach is timed to the **customer's local timezone**. Messages are **auto-translated** into the customer's detected language — a customer in Germany receives a message in German with no manual setup.
</Note>

## Escalation on high-value cases

When a case opens for an account above your configured threshold, Airdun alerts your team via Slack or email alongside the automated sequence, so a person can step in. The threshold is set under **Settings → Notifications → Escalation**. See [Notifications](/configuration/notifications).

## Enabling channels

Each channel has its own prerequisites — a verified sending domain for email, the Airdun snippet for the in-app wall. See [Channels Setup](/configuration/channels-setup) for the procedure.