# Notifications

> The Slack, Discord and Telegram alert channels: the payload each one posts and the HTTP request that carries it.

| Hook | Kind | Tier | Since | Summary |
| --- | --- | --- | --- | --- |
| [`boolean_smtp_alert_delivery_failure_fields`](/hooks/boolean_smtp_alert_delivery_failure_fields/) | filter | B | 1.0.0 | Filters the label/value fields shown for a delivery-failure notification. |
| [`boolean_smtp_discord_notification_payload`](/hooks/boolean_smtp_discord_notification_payload/) | filter | A | 1.0.0 | Filters the Discord webhook payload before it is sent. |
| [`boolean_smtp_notification_http_request_args`](/hooks/boolean_smtp_notification_http_request_args/) | filter | B | 1.0.0 | Filters the HTTP request arguments used for an outbound notification request. |
| [`boolean_smtp_notification_sslverify`](/hooks/boolean_smtp_notification_sslverify/) | filter | B | 1.0.0 | Filters whether outbound notification requests verify the remote SSL certificate. |
| [`boolean_smtp_oauth_failure_notified`](/hooks/boolean_smtp_oauth_failure_notified/) | action | B | 1.0.0 | Fires after an OAuth refresh failure has been handed to the supported notification channels. |
| [`boolean_smtp_slack_notification_payload`](/hooks/boolean_smtp_slack_notification_payload/) | filter | A | 1.0.0 | Filters the Slack webhook payload before it is sent. |
| [`boolean_smtp_telegram_notification_text`](/hooks/boolean_smtp_telegram_notification_text/) | filter | A | 1.0.0 | Filters the Telegram message text (HTML-formatted) before it is sent. |