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Outage mode lets you gracefully handle service disruptions by blocking outbound traffic and routing inbound calls to a fallback number. When you need to take your agents offline for maintenance or during an incident, outage mode ensures callers still reach a real person instead of getting disconnected.

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How It Works

When outage mode is enabled:
  • Inbound calls are automatically transferred to the fallback number configured on the receiving phone number. If no fallback number is set, the call is disconnected.
  • Outbound calls, web calls, SMS, and batch calls are all blocked.
When outage mode is disabled, all calls and messages operate normally.

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Setup

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Step 1: Configure fallback numbers

Before enabling outage mode, set up fallback numbers on the phone numbers you want to protect.
  1. Go to Dashboard > Phone Numbers
  2. Click on the phone number you want to configure
  3. Enter a fallback phone number in the Fallback Number field
  4. Save your changes
Fallback number requirements:
  • Must be in E.164 format (e.g., +14155551234)
  • Must be an external number — cannot be a Retell-managed number
  • Cannot be the same number it’s assigned to

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Step 2: Enable outage mode

When you need to activate outage mode:
  1. Go to Dashboard > Settings > Reliability
  2. Toggle System Outage Mode on
  3. All inbound calls will now transfer to their configured fallback numbers
When the disruption is resolved, toggle outage mode off to resume normal operations.

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API Configuration

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Set a fallback number on a phone number

Use the Update Phone Number endpoint: 
curl -X PATCH https://api.retellai.com/update-phone-number/+14155551234 \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "fallback_number": "+14155559999"
  }'

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Toggle outage mode

Outage mode can be toggled via the Dashboard under Settings > Reliability.