Configuration

All GrydNotifications settings are configured through GrydNotificationsOptions:

builder.Services.AddGrydNotifications(options =>
{
    // ... configuration here
});

GrydNotificationsOptions

Connection String

Required. PostgreSQL connection string for notification persistence and template storage.

options.UsePostgreSqlStorage("Host=localhost;Database=gryd_notifications;...");
// or
options.ConnectionString = "Host=localhost;Database=gryd_notifications;...";

Feature Toggles

Property	Type	Default	Description
EnableTemplates	bool	true	Enables Scriban template engine
EnableQueue	bool	true	Enables async queue processing. When false, sends synchronously
PersistNotifications	bool	true	Persists notifications in the database for auditing
NotificationRetentionDays	int	90	Days to retain sent/failed notifications before cleanup

options.EnableTemplates = true;
options.EnableQueue = true;
options.PersistNotifications = true;
options.NotificationRetentionDays = 90;

---

Email Options

Configure email sending via SMTP (MailKit).

options.Email.DefaultFrom = "noreply@myapp.com";
options.Email.DefaultFromName = "My Application";
options.Email.SmtpHost = "smtp.sendgrid.net";
options.Email.SmtpPort = 587;
options.Email.SmtpUseSsl = true;
options.Email.SmtpUsername = "apikey";
options.Email.SmtpPassword = "SG.xxxxxxxxx";

Properties

Property	Type	Default	Description
DefaultFrom	string	""	Default sender email address
DefaultFromName	string?	null	Default sender display name
SmtpHost	string?	null	SMTP server hostname
SmtpPort	int	587	SMTP server port
SmtpUseSsl	bool	true	Use SSL/TLS for SMTP connection
SmtpUsername	string?	null	SMTP authentication username
SmtpPassword	string?	null	SMTP authentication password
MaxAttachmentSizeMb	int	10	Maximum attachment size per email (MB), checked when the file is attached
MaxAttachmentsPerEmail	int	5	Maximum number of attachments per email
MaxRecipientsPerEmail	int	50	Maximum recipients (To + Cc + Bcc)
BulkBatchSize	int	100	Emails per batch in bulk operations
BulkDelayBetweenBatches	TimeSpan	1s	Rate limiting delay between batches

Using SendGrid instead of SMTP

To use SendGrid's HTTP API instead of SMTP, install the provider package and configure the API key:

// Install: dotnet add package GrydNotifications.Infrastructure
// SendGrid uses the SMTP credentials with host smtp.sendgrid.net
options.Email.SmtpHost = "smtp.sendgrid.net";
options.Email.SmtpUsername = "apikey";
options.Email.SmtpPassword = "SG.your_api_key_here";

---

Push Notification Options

Configure push notifications via Firebase Cloud Messaging (FCM).

options.Push.Enabled = true;
options.Push.DefaultTimeToLive = TimeSpan.FromHours(24);
options.Push.AutoRemoveInvalidTokens = true;

Properties

Property	Type	Default	Description
Enabled	bool	true	Enables the push notification channel
DefaultTimeToLive	TimeSpan	24h	Default TTL for push messages
MaxDeviceTokensPerMulticast	int	500	Max tokens per FCM multicast (FCM limit: 500)
StaleTokenThreshold	TimeSpan	90 days	Duration after which unused tokens are deactivated
AutoRemoveInvalidTokens	bool	true	Auto-remove tokens reported as invalid by FCM

Firebase Configuration

Place your Firebase service account JSON at the root of your project or configure the GOOGLE_APPLICATION_CREDENTIALS environment variable:

export GOOGLE_APPLICATION_CREDENTIALS="/path/to/firebase-adminsdk.json"

---

In-App Notification Options

Configure the in-app notification channel (drawer/bell notifications + SignalR real-time).

options.InApp.Enabled = true;
options.InApp.EnableSignalR = true;
options.InApp.HubPath = "/hubs/notifications";
options.InApp.RetentionDays = 90;
options.InApp.MaxUnreadPerUser = 200;

Properties

Property	Type	Default	Description
Enabled	bool	true	Enables in-app notification channel
RetentionDays	int	90	Days to retain in-app notifications
MaxUnreadPerUser	int	200	Max unread per user (oldest auto-marked as read)
DefaultTimeToLive	TimeSpan?	null	Default TTL for notifications (null = no expiration)
EnableSignalR	bool	true	Enables real-time delivery via SignalR
HubPath	string	/hubs/notifications	SignalR hub endpoint path

---

Retry Options

Configure retry policies for failed notification delivery.

options.Retry.MaxRetries = 3;
options.Retry.BackoffType = BackoffType.Exponential;
options.Retry.BaseDelay = TimeSpan.FromSeconds(5);
options.Retry.MaxDelay = TimeSpan.FromMinutes(5);
options.Retry.UseJitter = true;

Properties

Property	Type	Default	Description
MaxRetries	int	3	Maximum retry attempts before dead-lettering
BackoffType	BackoffType	Exponential	Backoff strategy
BaseDelay	TimeSpan	5s	Base delay for the first retry
MaxDelay	TimeSpan	5min	Maximum delay cap
UseJitter	bool	true	Adds randomized jitter to prevent thundering herd
NonRetryableReasons	HashSet<DeliveryFailureReason>	see below	Permanent failures that skip retry

Backoff Types

Type	Formula	Example (5s base)
Fixed	baseDelay	5s → 5s → 5s
Linear	baseDelay × attempt	5s → 10s → 15s
Exponential	baseDelay × 2^attempt	5s → 10s → 20s

Non-Retryable Failure Reasons

By default, these permanent failures skip retry entirely:

• InvalidRecipient — Email address doesn't exist
• InvalidTemplate — Template syntax error
• AuthenticationFailed — Provider credential error

---

Queue Options

Configure the in-memory notification processing queue (Channel<T>).

options.Queue.BatchSize = 10;
options.Queue.PollingInterval = TimeSpan.FromSeconds(5);
options.Queue.MaxConcurrency = 4;

Properties

Property	Type	Default	Description
BatchSize	int	10	Notifications dequeued per batch
PollingInterval	TimeSpan	5s	Polling interval when queue is empty
MaxConcurrency	int	4	Concurrent processors consuming the queue
MessageExpiration	TimeSpan?	null	Max time in queue before discard (null = no limit)

WARNING

The default queue uses Channel<T> in-memory. Messages are lost if the application restarts. For durable queuing in production, install GrydNotifications.Scheduling to delegate to GrydJobs.

---

Health Checks

// Basic registration
builder.Services.AddGrydNotificationsHealthChecks();

// With custom settings
builder.Services.AddGrydNotificationsHealthChecks(
    name: "grydnotifications",
    failureStatus: HealthStatus.Degraded,
    tags: ["grydnotifications", "notifications", "ready"]);

The health check monitors:

• Queue depth — Returns Degraded if queue depth exceeds 10,000
• Infrastructure availability — Returns Degraded on exceptions

GET /health

{
  "status": "Healthy",
  "entries": {
    "grydnotifications": {
      "status": "Healthy",
      "description": "GrydNotifications is running.",
      "data": {
        "queueDepth": 42
      }
    }
  }
}

---

appsettings.json Reference

Complete configuration example:

{
  "ConnectionStrings": {
    "Notifications": "Host=localhost;Database=gryd_notifications;Username=postgres;Password=postgres"
  },
  "GrydNotifications": {
    "EnableTemplates": true,
    "EnableQueue": true,
    "PersistNotifications": true,
    "NotificationRetentionDays": 90,
    "Email": {
      "DefaultFrom": "noreply@myapp.com",
      "DefaultFromName": "My App",
      "SmtpHost": "smtp.sendgrid.net",
      "SmtpPort": 587,
      "SmtpUseSsl": true,
      "SmtpUsername": "apikey",
      "SmtpPassword": "SG.xxxxx",
      "MaxAttachmentSizeMb": 10,
      "MaxAttachmentsPerEmail": 5,
      "MaxRecipientsPerEmail": 50,
      "BulkBatchSize": 100,
      "BulkDelayBetweenBatches": "00:00:01"
    },
    "Push": {
      "Enabled": true,
      "DefaultTimeToLive": "24:00:00",
      "MaxDeviceTokensPerMulticast": 500,
      "StaleTokenThreshold": "90.00:00:00",
      "AutoRemoveInvalidTokens": true
    },
    "InApp": {
      "Enabled": true,
      "RetentionDays": 90,
      "MaxUnreadPerUser": 200,
      "DefaultTimeToLive": null,
      "EnableSignalR": true,
      "HubPath": "/hubs/notifications"
    },
    "Retry": {
      "MaxRetries": 3,
      "BackoffType": "Exponential",
      "BaseDelay": "00:00:05",
      "MaxDelay": "00:05:00",
      "UseJitter": true
    },
    "Queue": {
      "BatchSize": 10,
      "PollingInterval": "00:00:05",
      "MaxConcurrency": 4,
      "MessageExpiration": null
    }
  }
}