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Email Delivery Monitoring Dashboard ​

This use case demonstrates a fan-in pattern where delivery, bounce, and complaint webhooks from three email providers—Resend, SendGrid, and Postmark—are normalized into a common schema and routed to a monitoring API and Slack alerts channel.

Architecture ​

mermaid
flowchart LR
    Resend[Resend Webhooks] --> S1[Source: Resend]
    SendGrid[SendGrid Webhooks] --> S2[Source: SendGrid]
    Postmark[Postmark Webhooks] --> S3[Source: Postmark]
    S1 --> R1[Route: Monitoring]
    S1 --> R2[Route: Slack Alerts]
    S2 --> R3[Route: Monitoring]
    S2 --> R4[Route: Slack Alerts]
    S3 --> R5[Route: Monitoring]
    S3 --> R6[Route: Slack Alerts]
    R1 --> |Transform| D1[Monitoring API]
    R2 --> |Transform + Filter| D2[Slack #email-alerts]
    R3 --> |Transform| D1
    R4 --> |Transform + Filter| D2
    R5 --> |Transform| D1
    R6 --> |Transform + Filter| D2

Flow:

  1. Three email providers send delivery/bounce/complaint webhooks to separate Hookbase sources
  2. Each source verifies the provider's signature
  3. Routes normalize each provider's schema into a common format
  4. All delivery events flow to a single monitoring API
  5. Bounces and complaints trigger Slack alerts

Key Challenge

Each provider uses a different payload format. SendGrid batches multiple events in a single array payload. The transforms handle all three schemas and normalize them into one unified structure.

Step 1: Create Sources ​

Create a source for each email provider with signature verification.

Resend Source ​

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/sources \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend Production",
    "slug": "resend-prod",
    "description": "Resend email delivery webhooks",
    "verificationConfig": {
      "type": "svix",
      "secret": "whsec_your_resend_webhook_signing_secret"
    }
  }'

Response:

json
{
  "data": {
    "id": "src_resend01",
    "name": "Resend Production",
    "slug": "resend-prod",
    "url": "https://api.hookbase.app/ingest/your-org/resend-prod",
    "verificationConfig": {
      "type": "svix"
    },
    "createdAt": "2026-03-07T10:00:00Z"
  }
}

TIP

Resend uses Svix under the hood for webhook delivery. Use the svix verification type with the signing secret from your Resend dashboard under Webhooks.

SendGrid Source ​

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/sources \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "SendGrid Production",
    "slug": "sendgrid-prod",
    "description": "SendGrid Event Webhook",
    "verificationConfig": {
      "type": "sendgrid",
      "publicKey": "YOUR_SENDGRID_VERIFICATION_KEY"
    }
  }'

Response:

json
{
  "data": {
    "id": "src_sgrid01",
    "name": "SendGrid Production",
    "slug": "sendgrid-prod",
    "url": "https://api.hookbase.app/ingest/your-org/sendgrid-prod",
    "verificationConfig": {
      "type": "sendgrid"
    },
    "createdAt": "2026-03-07T10:01:00Z"
  }
}

WARNING

SendGrid sends events as a JSON array containing multiple events in a single request. The transform in Step 4 handles this by iterating over the array.

Postmark Source ​

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/sources \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Postmark Production",
    "slug": "postmark-prod",
    "description": "Postmark delivery and bounce webhooks",
    "verificationConfig": {
      "type": "hmac",
      "header": "X-Postmark-Webhook-Token",
      "secret": "your_postmark_webhook_token",
      "algorithm": "plain"
    }
  }'

Response:

json
{
  "data": {
    "id": "src_pmrk01",
    "name": "Postmark Production",
    "slug": "postmark-prod",
    "url": "https://api.hookbase.app/ingest/your-org/postmark-prod",
    "verificationConfig": {
      "type": "hmac"
    },
    "createdAt": "2026-03-07T10:02:00Z"
  }
}

TIP

Configure this URL in your Postmark server's Webhooks settings. Select the Delivery, Bounce, Spam Complaint, and Open triggers.

Step 2: Create Destinations ​

Monitoring API Destination ​

This is the central endpoint that receives all normalized email events:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/destinations \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Email Monitoring API",
    "type": "http",
    "config": {
      "url": "https://monitoring.yourcompany.com/api/email-events",
      "method": "POST",
      "headers": {
        "Authorization": "Bearer YOUR_MONITORING_API_KEY",
        "Content-Type": "application/json"
      }
    },
    "retryConfig": {
      "maxAttempts": 5,
      "backoffMultiplier": 2,
      "initialInterval": 1000
    }
  }'

Response:

json
{
  "data": {
    "id": "dst_monitor01",
    "name": "Email Monitoring API",
    "type": "http",
    "createdAt": "2026-03-07T10:05:00Z"
  }
}

Slack Alerts Destination ​

Alert channel for bounces, complaints, and delivery failures:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/destinations \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Slack #email-alerts",
    "type": "slack",
    "config": {
      "url": "https://hooks.slack.com/services/YOUR/WEBHOOK/URL"
    },
    "retryConfig": {
      "maxAttempts": 2,
      "backoffMultiplier": 1.5,
      "initialInterval": 500
    }
  }'

Response:

json
{
  "data": {
    "id": "dst_slack01",
    "name": "Slack #email-alerts",
    "type": "slack",
    "createdAt": "2026-03-07T10:06:00Z"
  }
}

Step 3: Create Routes with Filters ​

Each source needs two routes: one to the monitoring API (all events) and one to Slack (bounces and complaints only). That means six routes total.

Monitoring Routes (All Events) ​

These routes send all email events from each provider to the monitoring API. No filter is needed—every event is forwarded.

Resend to Monitoring:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/routes \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend → Monitoring",
    "sourceId": "src_resend01",
    "destinationId": "dst_monitor01",
    "transformId": "tfm_resend_norm",
    "enabled": true
  }'

SendGrid to Monitoring:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/routes \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "SendGrid → Monitoring",
    "sourceId": "src_sgrid01",
    "destinationId": "dst_monitor01",
    "transformId": "tfm_sgrid_norm",
    "enabled": true
  }'

Postmark to Monitoring:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/routes \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Postmark → Monitoring",
    "sourceId": "src_pmrk01",
    "destinationId": "dst_monitor01",
    "transformId": "tfm_pmrk_norm",
    "enabled": true
  }'

Slack Alert Routes (Bounces and Complaints Only) ​

Create a shared filter for bounce and complaint events, then use it for all three Slack routes.

Bounce and Complaint Filter for Resend:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/filters \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend Bounces & Complaints",
    "conditions": [
      {
        "field": "type",
        "operator": "in",
        "value": ["email.bounced", "email.complained", "email.delivery_delayed"]
      }
    ],
    "logic": "AND"
  }'

Response:

json
{
  "data": {
    "id": "flt_resend_alert",
    "name": "Resend Bounces & Complaints"
  }
}

Bounce and Complaint Filter for SendGrid:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/filters \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "SendGrid Bounces & Complaints",
    "conditions": [
      {
        "field": "[0].event",
        "operator": "in",
        "value": ["bounce", "dropped", "spamreport", "deferred"]
      }
    ],
    "logic": "AND"
  }'

Response:

json
{
  "data": {
    "id": "flt_sgrid_alert",
    "name": "SendGrid Bounces & Complaints"
  }
}

TIP

SendGrid payloads are arrays, so the filter targets [0].event to check the first event in the batch. The transform will process the full array.

Bounce and Complaint Filter for Postmark:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/filters \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Postmark Bounces & Complaints",
    "conditions": [
      {
        "field": "RecordType",
        "operator": "in",
        "value": ["Bounce", "SpamComplaint"]
      }
    ],
    "logic": "AND"
  }'

Response:

json
{
  "data": {
    "id": "flt_pmrk_alert",
    "name": "Postmark Bounces & Complaints"
  }
}

Create the three Slack routes:

bash
# Resend → Slack
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/routes \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend → Slack Alerts",
    "sourceId": "src_resend01",
    "destinationId": "dst_slack01",
    "filterId": "flt_resend_alert",
    "transformId": "tfm_resend_slack",
    "enabled": true
  }'

# SendGrid → Slack
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/routes \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "SendGrid → Slack Alerts",
    "sourceId": "src_sgrid01",
    "destinationId": "dst_slack01",
    "filterId": "flt_sgrid_alert",
    "transformId": "tfm_sgrid_slack",
    "enabled": true
  }'

# Postmark → Slack
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/routes \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Postmark → Slack Alerts",
    "sourceId": "src_pmrk01",
    "destinationId": "dst_slack01",
    "filterId": "flt_pmrk_alert",
    "transformId": "tfm_pmrk_slack",
    "enabled": true
  }'

Step 4: Add Transforms ​

This is where the fan-in normalization happens. Each provider has a different payload format, and we need to map them all into a common schema.

Common normalized schema:

json
{
  "provider": "resend | sendgrid | postmark",
  "event_type": "delivered | bounced | complained | opened | clicked | deferred",
  "message_id": "provider-specific-id",
  "recipient": "[email protected]",
  "subject": "Email subject line",
  "timestamp": "2026-03-07T10:30:00Z",
  "metadata": {
    "bounce_type": "hard | soft",
    "bounce_reason": "description",
    "smtp_code": 550
  }
}

Resend Monitoring Transform ​

Resend sends individual events with a flat structure:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/transforms \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend → Normalized Email Event",
    "type": "jsonata",
    "config": {
      "expression": "(\n  $eventMap := {\n    \"email.sent\": \"sent\",\n    \"email.delivered\": \"delivered\",\n    \"email.bounced\": \"bounced\",\n    \"email.complained\": \"complained\",\n    \"email.opened\": \"opened\",\n    \"email.clicked\": \"clicked\",\n    \"email.delivery_delayed\": \"deferred\"\n  };\n  {\n    \"provider\": \"resend\",\n    \"event_type\": $lookup($eventMap, type),\n    \"message_id\": data.email_id,\n    \"recipient\": data.to[0],\n    \"subject\": data.subject,\n    \"timestamp\": data.created_at,\n    \"metadata\": type = \"email.bounced\" ? {\n      \"bounce_type\": data.bounce.type,\n      \"bounce_reason\": data.bounce.message,\n      \"smtp_code\": data.bounce.status_code\n    } : type = \"email.complained\" ? {\n      \"complaint_type\": data.complaint.complaint_type,\n      \"feedback_id\": data.complaint.feedback_id\n    } : type = \"email.clicked\" ? {\n      \"click_url\": data.click.link,\n      \"user_agent\": data.click.user_agent\n    } : {}\n  }\n)"
    }
  }'

Example Input (Resend email.bounced):

json
{
  "type": "email.bounced",
  "created_at": "2026-03-07T10:30:00Z",
  "data": {
    "email_id": "re_abc123xyz",
    "to": ["[email protected]"],
    "subject": "Your invoice is ready",
    "bounce": {
      "type": "hard",
      "message": "Mailbox does not exist",
      "status_code": 550
    }
  }
}

Example Output:

json
{
  "provider": "resend",
  "event_type": "bounced",
  "message_id": "re_abc123xyz",
  "recipient": "[email protected]",
  "subject": "Your invoice is ready",
  "timestamp": "2026-03-07T10:30:00Z",
  "metadata": {
    "bounce_type": "hard",
    "bounce_reason": "Mailbox does not exist",
    "smtp_code": 550
  }
}

SendGrid Monitoring Transform ​

SendGrid sends events as a JSON array with multiple events per request. The transform iterates over the array and outputs one normalized event per item:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/transforms \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "SendGrid → Normalized Email Events",
    "type": "jsonata",
    "config": {
      "expression": "(\n  $eventMap := {\n    \"processed\": \"sent\",\n    \"delivered\": \"delivered\",\n    \"bounce\": \"bounced\",\n    \"dropped\": \"bounced\",\n    \"deferred\": \"deferred\",\n    \"open\": \"opened\",\n    \"click\": \"clicked\",\n    \"spamreport\": \"complained\"\n  };\n  $map($, function($evt) {\n    {\n      \"provider\": \"sendgrid\",\n      \"event_type\": $lookup($eventMap, $evt.event),\n      \"message_id\": $evt.sg_message_id,\n      \"recipient\": $evt.email,\n      \"subject\": $evt.subject,\n      \"timestamp\": $fromMillis($evt.timestamp * 1000),\n      \"metadata\": $evt.event = \"bounce\" or $evt.event = \"dropped\" ? {\n        \"bounce_type\": $evt.type,\n        \"bounce_reason\": $evt.reason,\n        \"smtp_code\": $evt.status\n      } : $evt.event = \"click\" ? {\n        \"click_url\": $evt.url,\n        \"user_agent\": $evt.useragent\n      } : $evt.event = \"spamreport\" ? {\n        \"complaint_type\": \"spam\",\n        \"feedback_id\": $evt.sg_event_id\n      } : {}\n    }\n  })\n)"
    }
  }'

Important: SendGrid Batch Payloads

SendGrid sends up to 1,000 events per request as a JSON array. This transform uses $map() to iterate over every event in the batch and produces an array of normalized events. Your monitoring API must handle both single objects (from Resend/Postmark) and arrays (from SendGrid).

Example Input (SendGrid batch with 2 events):

json
[
  {
    "email": "[email protected]",
    "event": "delivered",
    "sg_message_id": "sg_msg_001.filter0001",
    "subject": "Welcome aboard",
    "timestamp": 1741340400,
    "sg_event_id": "sg_evt_001"
  },
  {
    "email": "[email protected]",
    "event": "bounce",
    "sg_message_id": "sg_msg_002.filter0001",
    "subject": "Your receipt",
    "timestamp": 1741340410,
    "type": "hard",
    "reason": "550 5.1.1 The email account does not exist",
    "status": "550",
    "sg_event_id": "sg_evt_002"
  }
]

Example Output:

json
[
  {
    "provider": "sendgrid",
    "event_type": "delivered",
    "message_id": "sg_msg_001.filter0001",
    "recipient": "[email protected]",
    "subject": "Welcome aboard",
    "timestamp": "2026-03-07T10:20:00Z",
    "metadata": {}
  },
  {
    "provider": "sendgrid",
    "event_type": "bounced",
    "message_id": "sg_msg_002.filter0001",
    "recipient": "[email protected]",
    "subject": "Your receipt",
    "timestamp": "2026-03-07T10:20:10Z",
    "metadata": {
      "bounce_type": "hard",
      "bounce_reason": "550 5.1.1 The email account does not exist",
      "smtp_code": "550"
    }
  }
]

Postmark Monitoring Transform ​

Postmark sends individual events with PascalCase field names:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/transforms \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Postmark → Normalized Email Event",
    "type": "jsonata",
    "config": {
      "expression": "(\n  $eventMap := {\n    \"Delivery\": \"delivered\",\n    \"Bounce\": \"bounced\",\n    \"SpamComplaint\": \"complained\",\n    \"Open\": \"opened\",\n    \"Click\": \"clicked\"\n  };\n  {\n    \"provider\": \"postmark\",\n    \"event_type\": $lookup($eventMap, RecordType),\n    \"message_id\": MessageID,\n    \"recipient\": Recipient ? Recipient : Email,\n    \"subject\": Subject,\n    \"timestamp\": DeliveredAt ? DeliveredAt : BouncedAt ? BouncedAt : ReceivedAt,\n    \"metadata\": RecordType = \"Bounce\" ? {\n      \"bounce_type\": Type = 1 ? \"hard\" : \"soft\",\n      \"bounce_reason\": Description,\n      \"smtp_code\": TypeCode\n    } : RecordType = \"SpamComplaint\" ? {\n      \"complaint_type\": \"spam\",\n      \"feedback_id\": ID\n    } : RecordType = \"Click\" ? {\n      \"click_url\": OriginalLink,\n      \"user_agent\": UserAgent\n    } : {}\n  }\n)"
    }
  }'

Example Input (Postmark Bounce):

json
{
  "RecordType": "Bounce",
  "Type": 1,
  "TypeCode": 1,
  "MessageID": "pm-msg-abc123",
  "Description": "Hard bounce - address does not exist",
  "Email": "[email protected]",
  "Subject": "Monthly report",
  "BouncedAt": "2026-03-07T10:35:00Z",
  "ServerID": 12345,
  "Tag": "monthly-report",
  "ID": 98765432
}

Example Output:

json
{
  "provider": "postmark",
  "event_type": "bounced",
  "message_id": "pm-msg-abc123",
  "recipient": "[email protected]",
  "subject": "Monthly report",
  "timestamp": "2026-03-07T10:35:00Z",
  "metadata": {
    "bounce_type": "hard",
    "bounce_reason": "Hard bounce - address does not exist",
    "smtp_code": 1
  }
}

Slack Alert Transforms ​

Each provider needs a Slack transform that formats bounce/complaint events as Block Kit messages.

Resend Slack Transform:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/transforms \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend → Slack Alert",
    "type": "jsonata",
    "config": {
      "expression": "(\n  $isBounce := type = \"email.bounced\";\n  $isComplaint := type = \"email.complained\";\n  $emoji := $isBounce ? \":warning:\" : $isComplaint ? \":rotating_light:\" : \":hourglass:\";\n  $label := $isBounce ? \"Email Bounced\" : $isComplaint ? \"Spam Complaint\" : \"Delivery Delayed\";\n  $color := $isBounce ? \"#e74c3c\" : $isComplaint ? \"#e91e63\" : \"#f39c12\";\n  {\n    \"attachments\": [\n      {\n        \"color\": $color,\n        \"blocks\": [\n          {\n            \"type\": \"header\",\n            \"text\": {\n              \"type\": \"plain_text\",\n              \"text\": $emoji & \" \" & $label & \" (Resend)\"\n            }\n          },\n          {\n            \"type\": \"section\",\n            \"fields\": [\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Recipient:*\\n\" & data.to[0]\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Subject:*\\n\" & data.subject\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Reason:*\\n\" & ($isBounce ? data.bounce.message : $isComplaint ? data.complaint.complaint_type : \"Temporary delivery issue\")\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Time:*\\n\" & data.created_at\n              }\n            ]\n          },\n          {\n            \"type\": \"context\",\n            \"elements\": [\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"Message ID: \" & data.email_id & \" | Provider: Resend\"\n              }\n            ]\n          }\n        ]\n      }\n    ]\n  }\n)"
    }
  }'

SendGrid Slack Transform:

This transform extracts only bounce/complaint events from the SendGrid batch array and formats them:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/transforms \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "SendGrid → Slack Alert",
    "type": "jsonata",
    "config": {
      "expression": "(\n  $alerts := $filter($, function($evt) {\n    $evt.event in [\"bounce\", \"dropped\", \"spamreport\", \"deferred\"]\n  });\n  $count := $count($alerts);\n  $first := $alerts[0];\n  $isBounce := $first.event = \"bounce\" or $first.event = \"dropped\";\n  $isSpam := $first.event = \"spamreport\";\n  $emoji := $isBounce ? \":warning:\" : $isSpam ? \":rotating_light:\" : \":hourglass:\";\n  $label := $isBounce ? \"Email Bounced\" : $isSpam ? \"Spam Report\" : \"Delivery Deferred\";\n  $color := $isBounce ? \"#e74c3c\" : $isSpam ? \"#e91e63\" : \"#f39c12\";\n  {\n    \"attachments\": [\n      {\n        \"color\": $color,\n        \"blocks\": [\n          {\n            \"type\": \"header\",\n            \"text\": {\n              \"type\": \"plain_text\",\n              \"text\": $emoji & \" \" & $label & \" (SendGrid)\" & ($count > 1 ? \" +\" & $string($count - 1) & \" more\" : \"\")\n            }\n          },\n          {\n            \"type\": \"section\",\n            \"fields\": [\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Recipient:*\\n\" & $first.email\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Subject:*\\n\" & $first.subject\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Reason:*\\n\" & ($first.reason ? $first.reason : $first.event)\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Events in batch:*\\n\" & $string($count)\n              }\n            ]\n          },\n          {\n            \"type\": \"context\",\n            \"elements\": [\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"Message ID: \" & $first.sg_message_id & \" | Provider: SendGrid\"\n              }\n            ]\n          }\n        ]\n      }\n    ]\n  }\n)"
    }
  }'

Postmark Slack Transform:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/transforms \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Postmark → Slack Alert",
    "type": "jsonata",
    "config": {
      "expression": "(\n  $isBounce := RecordType = \"Bounce\";\n  $isComplaint := RecordType = \"SpamComplaint\";\n  $emoji := $isBounce ? \":warning:\" : \":rotating_light:\";\n  $label := $isBounce ? \"Email Bounced\" : \"Spam Complaint\";\n  $color := $isBounce ? \"#e74c3c\" : \"#e91e63\";\n  {\n    \"attachments\": [\n      {\n        \"color\": $color,\n        \"blocks\": [\n          {\n            \"type\": \"header\",\n            \"text\": {\n              \"type\": \"plain_text\",\n              \"text\": $emoji & \" \" & $label & \" (Postmark)\"\n            }\n          },\n          {\n            \"type\": \"section\",\n            \"fields\": [\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Recipient:*\\n\" & Email\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Subject:*\\n\" & Subject\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Reason:*\\n\" & ($isBounce ? Description : \"User marked as spam\")\n              },\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"*Bounce Type:*\\n\" & ($isBounce ? (Type = 1 ? \"Hard bounce\" : \"Soft bounce\") : \"N/A\")\n              }\n            ]\n          },\n          {\n            \"type\": \"context\",\n            \"elements\": [\n              {\n                \"type\": \"mrkdwn\",\n                \"text\": \"Message ID: \" & MessageID & \" | Provider: Postmark | Server: \" & $string(ServerID)\"\n              }\n            ]\n          }\n        ]\n      }\n    ]\n  }\n)"
    }
  }'

Example Slack Output (Postmark Bounce):

json
{
  "attachments": [
    {
      "color": "#e74c3c",
      "blocks": [
        {
          "type": "header",
          "text": {
            "type": "plain_text",
            "text": ":warning: Email Bounced (Postmark)"
          }
        },
        {
          "type": "section",
          "fields": [
            {
              "type": "mrkdwn",
              "text": "*Recipient:*\n[email protected]"
            },
            {
              "type": "mrkdwn",
              "text": "*Subject:*\nMonthly report"
            },
            {
              "type": "mrkdwn",
              "text": "*Reason:*\nHard bounce - address does not exist"
            },
            {
              "type": "mrkdwn",
              "text": "*Bounce Type:*\nHard bounce"
            }
          ]
        },
        {
          "type": "context",
          "elements": [
            {
              "type": "mrkdwn",
              "text": "Message ID: pm-msg-abc123 | Provider: Postmark | Server: 12345"
            }
          ]
        }
      ]
    }
  ]
}

Step 5: Test the Pipeline ​

Send test payloads to each source to verify the full pipeline.

Test Resend Webhook ​

bash
curl -X POST https://api.hookbase.app/ingest/your-org/resend-prod \
  -H "Content-Type: application/json" \
  -H "svix-id: test_msg_001" \
  -H "svix-timestamp: 1741340400" \
  -H "svix-signature: v1,test_signature" \
  -d '{
    "type": "email.bounced",
    "created_at": "2026-03-07T10:30:00Z",
    "data": {
      "email_id": "re_test_bounce_001",
      "from": "[email protected]",
      "to": ["[email protected]"],
      "subject": "Your invoice #1234",
      "bounce": {
        "type": "hard",
        "message": "550 5.1.1 Mailbox does not exist",
        "status_code": 550
      },
      "created_at": "2026-03-07T10:30:00Z"
    }
  }'

Test SendGrid Webhook (Batch Payload) ​

bash
curl -X POST https://api.hookbase.app/ingest/your-org/sendgrid-prod \
  -H "Content-Type: application/json" \
  -H "X-Twilio-Email-Event-Webhook-Signature: test_signature" \
  -H "X-Twilio-Email-Event-Webhook-Timestamp: 1741340400" \
  -d '[
    {
      "email": "[email protected]",
      "event": "delivered",
      "sg_message_id": "sg_test_001.filter0001",
      "subject": "Welcome to our platform",
      "timestamp": 1741340400,
      "sg_event_id": "sg_evt_test_001",
      "smtp-id": "<[email protected]>"
    },
    {
      "email": "[email protected]",
      "event": "bounce",
      "sg_message_id": "sg_test_002.filter0001",
      "subject": "Your account summary",
      "timestamp": 1741340410,
      "type": "hard",
      "reason": "550 5.1.1 The email account that you tried to reach does not exist",
      "status": "550",
      "sg_event_id": "sg_evt_test_002"
    },
    {
      "email": "[email protected]",
      "event": "delivered",
      "sg_message_id": "sg_test_003.filter0001",
      "subject": "Password reset",
      "timestamp": 1741340420,
      "sg_event_id": "sg_evt_test_003"
    }
  ]'

Test Postmark Webhook ​

bash
curl -X POST https://api.hookbase.app/ingest/your-org/postmark-prod \
  -H "Content-Type: application/json" \
  -H "X-Postmark-Webhook-Token: your_postmark_webhook_token" \
  -d '{
    "RecordType": "Bounce",
    "Type": 1,
    "TypeCode": 1,
    "MessageID": "pm_test_bounce_001",
    "Description": "Hard bounce - The email account does not exist",
    "Email": "[email protected]",
    "Subject": "Order confirmation #5678",
    "BouncedAt": "2026-03-07T10:35:00Z",
    "ServerID": 12345,
    "Tag": "order-confirmation",
    "ID": 99990001
  }'

Verify Deliveries ​

Check that events were delivered to both destinations:

bash
curl https://api.hookbase.app/api/organizations/{orgId}/deliveries?limit=20 \
  -H "Authorization: Bearer YOUR_TOKEN"

You should see deliveries for each test:

  • Resend test: 2 deliveries (Monitoring API + Slack alert for bounce)
  • SendGrid test: 2 deliveries (Monitoring API with 3 normalized events + Slack alert for bounce)
  • Postmark test: 2 deliveries (Monitoring API + Slack alert for bounce)

TIP

Use the Events page in the Hookbase dashboard to inspect the raw and transformed payloads side by side for each delivery.

Production Considerations ​

1. Enable Deduplication on All Sources ​

Email providers may retry webhook delivery. Prevent duplicate processing:

bash
# Resend - deduplicate by Svix message ID (available in headers)
curl -X PATCH https://api.hookbase.app/api/organizations/{orgId}/sources/src_resend01 \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "deduplicationConfig": {
      "enabled": true,
      "keyPath": "data.email_id",
      "windowSeconds": 86400
    }
  }'

# SendGrid - deduplicate by sg_event_id from first event in batch
curl -X PATCH https://api.hookbase.app/api/organizations/{orgId}/sources/src_sgrid01 \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "deduplicationConfig": {
      "enabled": true,
      "keyPath": "[0].sg_event_id",
      "windowSeconds": 86400
    }
  }'

# Postmark - deduplicate by MessageID
curl -X PATCH https://api.hookbase.app/api/organizations/{orgId}/sources/src_pmrk01 \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "deduplicationConfig": {
      "enabled": true,
      "keyPath": "MessageID",
      "windowSeconds": 86400
    }
  }'

2. Configure Circuit Breakers ​

Protect your monitoring API from overload during email incidents (large bounce storms can generate thousands of events):

bash
curl -X PATCH https://api.hookbase.app/api/organizations/{orgId}/destinations/dst_monitor01 \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "circuitBreakerConfig": {
      "enabled": true,
      "failureThreshold": 15,
      "windowSeconds": 60,
      "resetTimeoutSeconds": 300
    }
  }'

3. Set Up Notification Channels ​

Get alerted when deliveries to your monitoring API fail:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/notification-channels \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Email Pipeline Alerts",
    "type": "slack",
    "config": {
      "url": "https://hooks.slack.com/services/YOUR/OPS-ALERT/URL"
    },
    "events": ["delivery.failed", "destination.circuit_breaker.opened", "source.verification.failed"],
    "filters": {
      "sourceIds": ["src_resend01", "src_sgrid01", "src_pmrk01"],
      "destinationIds": ["dst_monitor01"]
    }
  }'

4. Set Up Failover for Monitoring ​

Ensure email events reach a backup if the primary monitoring API goes down:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/destinations \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Monitoring API Backup",
    "type": "http",
    "config": {
      "url": "https://monitoring-backup.yourcompany.com/api/email-events",
      "method": "POST",
      "headers": {
        "Authorization": "Bearer YOUR_BACKUP_API_KEY",
        "Content-Type": "application/json"
      }
    }
  }'
bash
# Apply failover to all three monitoring routes
for route_id in rte_resend_mon rte_sgrid_mon rte_pmrk_mon; do
  curl -X PATCH https://api.hookbase.app/api/organizations/{orgId}/routes/${route_id} \
    -H "Authorization: Bearer YOUR_TOKEN" \
    -H "Content-Type: application/json" \
    -d '{
      "failoverConfig": {
        "enabled": true,
        "destinationId": "dst_backup01",
        "triggerAfterAttempts": 3
      }
    }'
done

5. Use Scoped API Keys ​

Create restricted API keys for each email provider's webhook configuration:

bash
curl -X POST https://api.hookbase.app/api/organizations/{orgId}/api-keys \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Email Provider Ingestion",
    "scopes": ["events:create"],
    "sourceIds": ["src_resend01", "src_sgrid01", "src_pmrk01"],
    "expiresAt": "2027-03-07T00:00:00Z"
  }'

See Also ​

Released under the MIT License.

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