Notifications Configuration — Options & Health Checks

This page documents all configuration options, health checks, and OpenTelemetry instrumentation for the notification engine and its providers.

Core

{
  "Notifications": {
    "MaxParallelDeliveries": 8
  }
}

| Property | Default | Description | |----------|---------|-------------| | MaxParallelDeliveries | 8 | Max concurrent delivery messages (Wolverine queue parallelism) |

Email

{
  "Notifications": {
    "Email": {
      "Provider": "Smtp",
      "SenderAddress": "noreply@clinic.example.com",
      "SenderName": "Clinic Portal"
    }
  }
}

SMTP

{
  "Notifications": {
    "Smtp": {
      "Host": "smtp.example.com",
      "Port": 587,
      "UseSsl": true,
      "Username": "user",
      "Password": "vault:secret/data/smtp#password",
      "TimeoutSeconds": 30
    }
  }
}

Brevo

{
  "Notifications": {
    "Brevo": {
      "ApiKey": "vault:secret/data/brevo#api-key",
      "DefaultSenderEmail": "noreply@clinic.example.com",
      "DefaultSenderName": "Clinic Portal",
      "DefaultSmsSenderId": "CLINIC",
      "BaseUrl": "https://api.brevo.com/v3",
      "TimeoutSeconds": 30
    }
  }
}

SendGrid

{
  "Notifications": {
    "Email": {
      "SendGrid": {
        "ApiKey": "vault:secret/data/sendgrid#api-key",
        "DefaultSenderEmail": "noreply@clinic.example.com",
        "DefaultSenderName": "Clinic Portal",
        "SandboxMode": false,
        "TimeoutSeconds": 30
      }
    }
  }
}

Twilio

{
  "Notifications": {
    "Twilio": {
      "AccountSid": "ACxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
      "AuthToken": "vault:secret/data/twilio#auth-token",
      "DefaultSmsFrom": "+15551234567",
      "DefaultWhatsAppFrom": "whatsapp:+14155238886",
      "MessagingServiceSid": null,
      "TimeoutSeconds": 30
    }
  }
}

SMS

{
  "Notifications": {
    "Sms": {
      "Provider": "Brevo",
      "SenderId": "CLINIC"
    }
  }
}

Mobile Push (FCM)

{
  "Notifications": {
    "MobilePush": {
      "Provider": "GoogleFcm",
      "GoogleFcm": {
        "ProjectId": "my-firebase-project",
        "ServiceAccountJson": "vault:secret/data/fcm#service-account",
        "BaseAddress": "https://fcm.googleapis.com/",
        "TimeoutSeconds": 30
      }
    }
  }
}

Azure Communication Services — Email

{
  "AzureCommunicationServices": {
    "Email": {
      "ConnectionString": "endpoint=...;accesskey=...",
      "SenderAddress": "noreply@mydomain.com",
      "TimeoutSeconds": 120
    }
  }
}

Azure Communication Services — SMS

{
  "AzureCommunicationServices": {
    "Sms": {
      "ConnectionString": "endpoint=...;accesskey=...",
      "FromPhoneNumber": "+15551234567",
      "TimeoutSeconds": 30
    }
  }
}

AWS SNS — SMS

{
  "Notifications": {
    "Sms": {
      "AwsSns": {
        "Region": "eu-west-1",
        "SenderId": "MYAPP",
        "SmsType": "Transactional",
        "TimeoutSeconds": 30
      }
    }
  }
}

| Property | Default | Description | |----------|---------|-------------| | Region | — | AWS region (required) | | SenderId | null | Alphanumeric sender ID (1-11 chars, region-dependent) | | SmsType | "Transactional" | "Transactional" or "Promotional" | | OriginationNumber | null | E.164 originating number | | AccessKeyId | null | AWS access key (uses default credential chain when null) | | SecretAccessKey | null | AWS secret key (required if AccessKeyId set) |

AWS SNS — Mobile Push

{
  "Notifications": {
    "MobilePush": {
      "AwsSns": {
        "Region": "eu-west-1",
        "PlatformApplicationArn": "arn:aws:sns:eu-west-1:123456789:app/GCM/my-app",
        "TimeoutSeconds": 30
      }
    }
  }
}

| Property | Default | Description | |----------|---------|-------------| | Region | — | AWS region (required) | | PlatformApplicationArn | — | SNS Platform Application ARN (required) | | AccessKeyId | null | AWS access key (uses default credential chain when null) | | SecretAccessKey | null | AWS secret key (required if AccessKeyId set) |

Azure Notification Hubs — Mobile Push

{
  "Notifications": {
    "AzureNotificationHubs": {
      "ConnectionString": "Endpoint=sb://...",
      "HubName": "my-notification-hub",
      "TimeoutSeconds": 30
    }
  }
}

SignalR

{
  "Notifications": {
    "SignalR": {
      "RedisConnectionString": "redis:6379"
    }
  }
}

Web Push (VAPID)

{
  "Notifications": {
    "Push": {
      "VapidSubject": "mailto:admin@clinic.example.com",
      "VapidPublicKey": "BFx...",
      "VapidPrivateKey": "vault:secret/data/webpush#private-key"
    }
  }
}

SSE

{
  "Notifications": {
    "Sse": {
      "HeartbeatIntervalSeconds": 30,
      "MaxConnectionsPerUser": 10,
      "MaxBufferSize": 100
    }
  }
}

| Option | Default | Description | |--------|---------|-------------| | HeartbeatIntervalSeconds | 30 | Keep-alive interval through proxies | | MaxConnectionsPerUser | 10 | Concurrent SSE connections per user (covers multiple tabs/devices) | | MaxBufferSize | 100 | Messages buffered per connection before oldest are dropped |

Zulip

{
  "Notifications": {
    "Zulip": {
      "DefaultStream": "alerts",
      "DefaultTopic": "system",
      "Bot": {
        "BaseUrl": "https://zulip.example.com",
        "BotEmail": "notification-bot@zulip.example.com",
        "ApiKey": "vault:secret/data/zulip#api-key",
        "TimeoutSeconds": 30
      }
    }
  }
}

Health checks

Notification channel providers register opt-in health checks:

builder.Services.AddHealthChecks()
    .AddGranitSmtpHealthCheck()
    .AddGranitAwsSesHealthCheck()
    .AddGranitBrevoHealthCheck()
    .AddGranitAcsEmailHealthCheck()
    .AddGranitAcsSmsHealthCheck()
    .AddGranitAzureNotificationHubsHealthCheck()
    .AddGranitAwsSnsSmsHealthCheck()
    .AddGranitAwsSnsMobilePushHealthCheck()
    .AddGranitScalewayEmailHealthCheck()
    .AddGranitSendGridHealthCheck()
    .AddGranitTwilioHealthCheck()
    .AddGranitZulipHealthCheck();

| Provider | Extension | Probe | Tags | |----------|-----------|-------|------| | SMTP | AddGranitSmtpHealthCheck() | EHLO handshake via MailKit | readiness | | SES | AddGranitAwsSesHealthCheck() | GetAccount() — Degraded if sending paused | readiness, startup | | Brevo | AddGranitBrevoHealthCheck() | GET /account | readiness | | ACS Email | AddGranitAcsEmailHealthCheck() | SendAsync probe | readiness | | ACS SMS | AddGranitAcsSmsHealthCheck() | SendAsync probe | readiness | | Azure Notification Hubs | AddGranitAzureNotificationHubsHealthCheck() | Hub description retrieval | readiness | | SNS SMS | AddGranitAwsSnsSmsHealthCheck() | SNS API connectivity check | readiness, startup | | SNS Mobile Push | AddGranitAwsSnsMobilePushHealthCheck() | SNS Platform Application check | readiness, startup | | Scaleway TEM | AddGranitScalewayEmailHealthCheck() | GET /emails?page_size=1 | readiness, startup | | SendGrid | AddGranitSendGridHealthCheck() | GET /scopes | readiness, startup | | Twilio | AddGranitTwilioHealthCheck() | GET /Accounts/{sid}.json | readiness, startup | | Zulip | AddGranitZulipHealthCheck() | GET /api/v1/users/me (Bot auth) | readiness |

All checks sanitize error messages — credentials, hostnames, and API keys are never exposed in the health check response. Every check enforces a 10-second defensive timeout via .WaitAsync() to prevent blocking Kubernetes probe cycles.

OpenTelemetry

All fan-out and delivery operations are traced via ActivitySource:

| Activity name | Description | |---------------|-------------| | notifications.fanout | Fan-out of a NotificationTrigger into delivery commands | | notifications.deliver | Delivery of a single DeliverNotificationCommand via a channel |

Tags: notifications.type, notifications.channel, notifications.delivery_id, notifications.notification_id, notifications.recipient_count, notifications.delivery_count, notifications.success.