Overview

Throttling controls the speed at which messages are sent to your audience. This feature helps you manage server capacity by preventing sudden traffic surges when sending push notifications to a large number of users.

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Benefits

• Manage server load - Prevent your servers from becoming overwhelmed by spreading out notification delivery
• Maintain performance - Keep your website or app responsive during large-scale notification campaigns
• Control user experience - Ensure a consistent experience for all users by managing traffic flow

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Configuration options

Throttling must be enabled at the global settings level to be available for use.

Global throttling settings

Enable throttling for all push messages under Settings > Push & In-App > Throttling. Once enabled, this setting applies to all push notifications by default, but can be overridden for individual messages.

Per-message throttling override

You can customize throttling for individual notifications:

1. During notification creation, check the "Override throttling setting" box
2. Set your desired messages-per-minute rate
3. To disable throttling for a specific message, enter "0" in the messages-per-minute field

For API-sent notifications, use the throttle_rate_per_minute property.

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Global throttling required for override

Throttling must be enabled at the global settings level to be available for any use.

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How throttling works

Rate conversion process

OneSignal converts your per-minute setting to a per-second rate to optimize delivery:

1. The system divides your throttle rate by 60 (seconds per minute)
2. The result is rounded down to the nearest whole number (OneSignal can't send partial messages)
3. This per-second rate is then applied throughout the delivery process

Example:

• You set: 1019 messages per minute
• Calculation: 1019 ÷ 60 = 16.98 messages per second
• Rounded down: 16 messages per second
• Actual delivery rate: 16 × 60 = 960 messages per minute
• Difference: 59 fewer messages per minute than the set rate

This conversion results in more efficient processing by eliminating delays between batches.

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Limitations and Considerations

24-Hour Delivery Window

All throttled notifications must complete delivery within 24 hours of being sent. If your throttling rate would cause delivery to exceed 24 hours, OneSignal automatically adjusts the rate to ensure completion within this timeframe.

Example: If you set a 10-messages-per-minute rate for 20,000 users (which would take ~33 hours), OneSignal will automatically increase it to approximately 14 messages per minute to complete delivery within 24 hours.

Compatibility with Other Features

Timezone and Intelligent Delivery

Throttling takes precedence over Timezone and Intelligent Delivery options. When throttling is enabled, these features will be ignored for that notification.

To use Timezone or Intelligent Delivery:

• Disable throttling for that specific notification
• Set "Override throttling setting" to "0"
• For API notifications, set throttle_rate_per_minute: 0

Journeys & Automated Messages

Throttling is not supported for:

• Journeys
• Automated Messages

These features trigger notifications as users enter segments, naturally distributing sends over time.

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Availability

Throttling is only available for:

• Push notifications sent via the Create notification API
• Push notifications created through the Messages > New Push interface

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