# Notification Retries

This document describes the retry mechanism for failed notification deliveries.

## Overview

The retry system ensures reliable notification delivery even when temporary failures occur.

## Retry Strategy

### Exponential Backoff
- Initial delay: 5 seconds
- Maximum delay: 1 hour
- Backoff multiplier: 2x

### Retry Limits
- Maximum attempts: 10
- Maximum retry duration: 24 hours

### Retry Conditions
- Network errors: Always retry
- HTTP 5xx errors: Always retry
- HTTP 429 (rate limit): Retry with Retry-After header
- HTTP 4xx errors: Do not retry (permanent failure)

## Dead Letter Queue

Notifications that exceed retry limits are moved to the dead letter queue for:
- Manual inspection
- Automatic alerting
- Scheduled reprocessing

## Monitoring

Retry metrics are exposed for:
- Retry count per notification
- Success rate after retries
- Average retry duration