Notification Channels
Notification Channels
Section titled “Notification Channels”Notification channels are the destinations Mantis delivers event notifications to
(deployment results, target offline, certificate expiry, and so on). Create and
manage them in Lens under Notifications → Channels, or via the
/api/v1/notifications/channels API. Managing channels requires the notifications:create, notifications:update, and
notifications:delete permissions for creating, editing, and deleting channels respectively.
Supported channel types:
| Type | Destination |
|---|---|
| An SMTP server (see below) | |
| Webhook | An HTTPS endpoint (Standard Webhooks, optionally HMAC-signed) |
| Slack | A Slack incoming-webhook URL |
| Teams | A Microsoft Teams Power Automate workflow URL |
| Discord | A Discord webhook URL |
Email (SMTP) channels
Section titled “Email (SMTP) channels”An email channel delivers notifications through an SMTP server. Configure these fields when creating or editing an email channel:
| Field | Required | Description |
|---|---|---|
smtp_host | Yes | SMTP server hostname |
smtp_port | Yes | SMTP server port (see TLS modes below) |
smtp_from_address | Yes | Envelope sender address (MAIL FROM) |
smtp_from_name | No | Display name for the sender |
smtp_username | No | SMTP AUTH username (omit for an unauthenticated relay) |
smtp_password | No | SMTP AUTH password — encrypted at rest and never returned |
smtp_use_tls | No | Whether to use TLS (default: true) |
The password is encrypted with AES-256-GCM, bound to the channel (so a stored secret cannot be reused on another channel), and is never logged or returned by the API.
TLS modes
Section titled “TLS modes”The transport security mode is derived from smtp_use_tls and the port:
smtp_use_tls | Port | Mode |
|---|---|---|
true | 465 | Implicit TLS (SMTPS — TLS from the first byte) |
true | any other (e.g. 587) | STARTTLS (opportunistic upgrade) |
false | any | Plaintext (no transport security) |
TLS uses the same rustls + aws-lc-rs stack as the rest of Mantis. Leave
smtp_use_tls at its true default unless you are sending to a trusted local
relay; with plaintext, credentials travel in the clear.
Testing a channel
Section titled “Testing a channel”Use the Test action in Lens (or POST /api/v1/notifications/channels/{id}/test) to send a test message. For an email
channel this performs a self-send to smtp_from_address, exercising the full
path — DNS/connection, TLS negotiation, AUTH, and message construction — and
reports success or the specific failure.
Delivery and retries
Section titled “Delivery and retries”Deliveries are processed by Mandible’s notification worker. A transient failure (connection error, timeout, SMTP 4xx, or a temporary DNS failure) is retried with exponential backoff. A permanent failure (SMTP 5xx reject, an unparseable sender/recipient address, or a missing/undecryptable SMTP configuration) is dead-lettered immediately rather than retried, since a retry cannot succeed. A per-channel circuit breaker pauses delivery to a channel that is failing repeatedly.