Delivery Pipeline Resilience

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Notification Send Retries

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Retry Conditions

Courier will attempt to resend a notification under the following circumstances:

• No response from the integration (e.g., network connection lost)
• Integration response indicates a temporary issue (e.g., server overload, rate limit exceeded)
• Uncaught exception in Courier’s pipeline

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Retry Strategy

Our retry strategy employs an exponential backoff approach:

1. Immediate retry for the first 10 attempts
2. 1-hour delay before the 11th attempt
3. 2-hour delay before the 12th attempt
4. 3-hour delay for attempts 13 through 25

This strategy spans 72 hours (3 days), maximizing the chances of successful delivery.

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Delivery Status Check Retries

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Retry Conditions

Courier will retry delivery status checks under these conditions:

• No response from the integration (e.g., network connection lost)
• Integration response indicates a temporary issue (e.g., server overload)
• Temporary failure in resolving the delivery status
• Uncaught exception in Courier’s pipeline

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Retry Strategy

We employ the same exponential backoff strategy for status checks:

1. Immediate retry for the first 10 attempts
2. 1-hour delay before the 11th attempt
3. 2-hour delay before the 12th attempt
4. 3-hour delay for attempts 13 through 25

This approach ensures thorough tracking of delivery statuses over a 72-hour period.

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Outbound Webhook Delivery Retries

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Retry Conditions

Courier will attempt to retry outbound webhook delivery under the following circumstances:

• Internal Courier errors occur
• Network errors are encountered
• Certain retryable HTTP errors are received

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Retry Strategy

Our outbound webhook retry strategy employs an exponential backoff approach:

1. Initial retries with increasing delays: 5, 10, 20, 40, 60, 120, 240, 480, 720, 900 seconds
2. After the 10th retry, a consistent 15-minute delay is used for subsequent attempts
3. Up to 296 retry attempts are made, spanning a maximum of 3 days

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Courier Status Page

You can track Courier’s services status here