### Sending Metrics (via `/v1/analytics/metrics`)
These metrics track the lifecycle and performance of your outbound emails:
- **Volume Metrics**: Messages accepted, delivered, failed, queued
- **Engagement Metrics**: Opens, clicks, unsubscribes
- **Deliverability Metrics**: Bounces (permanent and temporary), complaints (spam reports)
- **Rate Metrics**: Delivered rate, open rate, click rate, bounce rate
- **ESP-Specific Metrics**: Performance broken down by email service provider

See [metric definitions](https://documentation.mailgun.com/docs/mailgun/user-manual/reporting/metric-definitions) for a complete list of available metrics.