Resend Integration

Receive and route Resend webhooks for email delivery, engagement, and bounce events.

Setup

1. Create a Source in Hookbase

Resend uses Svix under the hood for webhook delivery, which signs payloads using HMAC-SHA256 with a base64-encoded signature in the webhook-signature header.

bash

curl -X POST https://api.hookbase.app/api/sources \
  -H "Authorization: Bearer whr_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Resend Production",
    "slug": "resend",
    "verificationConfig": {
      "type": "svix",
      "secret": "whsec_..."
    }
  }'

Save your webhook URL:

https://api.hookbase.app/ingest/{orgSlug}/resend

2. Configure Resend Webhook

Go to Resend Dashboard → Webhooks
Click Add webhook
Enter your Hookbase ingest URL
Select the events you want to receive
Click Create
Copy the Signing secret (starts with whsec_) and update your Hookbase source

3. Create Routes

bash

# Create destination for your email event handler
curl -X POST https://api.hookbase.app/api/destinations \
  -H "Authorization: Bearer whr_your_api_key" \
  -d '{"name": "Email Events Handler", "url": "https://api.myapp.com/webhooks/resend"}'

# Create route
curl -X POST https://api.hookbase.app/api/routes \
  -H "Authorization: Bearer whr_your_api_key" \
  -d '{"name": "Resend to Email Handler", "sourceId": "src_...", "destinationIds": ["dst_..."]}'

Signature Verification

Resend uses Svix for webhook delivery. The signature is sent across three headers:

Header	Description
`webhook-id`	Unique message ID
`webhook-timestamp`	Unix timestamp (seconds)
`webhook-signature`	`v1,<base64-encoded-signature>`

Hookbase verifies Svix signatures automatically:

json

{
  "verificationConfig": {
    "type": "svix",
    "secret": "whsec_..."
  }
}

Timestamp Tolerance

Svix signatures include a timestamp. Hookbase rejects webhooks older than 5 minutes by default to prevent replay attacks.

Common Events

email.sent

Triggered when an email is accepted by Resend for delivery.

json

{
  "type": "email.sent",
  "created_at": "2026-03-07T12:00:00.000Z",
  "data": {
    "email_id": "em_1234567890",
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Your order has been confirmed",
    "created_at": "2026-03-07T12:00:00.000Z"
  }
}

email.delivered

Triggered when an email is successfully delivered to the recipient's mail server.

json

{
  "type": "email.delivered",
  "created_at": "2026-03-07T12:00:02.000Z",
  "data": {
    "email_id": "em_1234567890",
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Your order has been confirmed",
    "created_at": "2026-03-07T12:00:00.000Z"
  }
}

email.opened

Triggered when a recipient opens the email (requires open tracking enabled).

json

{
  "type": "email.opened",
  "created_at": "2026-03-07T12:05:00.000Z",
  "data": {
    "email_id": "em_1234567890",
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Your order has been confirmed",
    "created_at": "2026-03-07T12:00:00.000Z"
  }
}

email.clicked

Triggered when a recipient clicks a link in the email (requires click tracking enabled).

json

{
  "type": "email.clicked",
  "created_at": "2026-03-07T12:06:00.000Z",
  "data": {
    "email_id": "em_1234567890",
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Your order has been confirmed",
    "click": {
      "link": "https://myapp.com/orders/12345",
      "timestamp": "2026-03-07T12:06:00.000Z"
    },
    "created_at": "2026-03-07T12:00:00.000Z"
  }
}

email.bounced

Triggered when an email bounces (permanent delivery failure).

json

{
  "type": "email.bounced",
  "created_at": "2026-03-07T12:00:03.000Z",
  "data": {
    "email_id": "em_1234567890",
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Your order has been confirmed",
    "bounce": {
      "message": "550 5.1.1 The email account that you tried to reach does not exist."
    },
    "created_at": "2026-03-07T12:00:00.000Z"
  }
}

email.complained

Triggered when a recipient marks the email as spam.

json

{
  "type": "email.complained",
  "created_at": "2026-03-07T14:00:00.000Z",
  "data": {
    "email_id": "em_1234567890",
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Your order has been confirmed",
    "created_at": "2026-03-07T12:00:00.000Z"
  }
}

Transform Examples

Slack Alert for Bounces and Complaints

javascript

function transform(payload) {
  const data = payload.data;
  const isBounce = payload.type === 'email.bounced';
  const title = isBounce ? 'Email Bounced' : 'Spam Complaint';
  const color = isBounce ? 'warning' : 'danger';

  return {
    attachments: [{
      color: color,
      title: title,
      fields: [
        { title: "To", value: data.to.join(', '), short: true },
        { title: "Subject", value: data.subject, short: true },
        { title: "From", value: data.from, short: true },
        { title: "Email ID", value: data.email_id, short: true }
      ],
      footer: isBounce && data.bounce ? data.bounce.message : "Marked as spam by recipient",
      ts: Math.floor(new Date(payload.created_at).getTime() / 1000)
    }]
  };
}

Email Analytics Format

javascript

function transform(payload) {
  const data = payload.data;

  return {
    email_id: data.email_id,
    event_type: payload.type.replace('email.', ''),
    from: data.from,
    to: data.to,
    subject: data.subject,
    link_clicked: data.click ? data.click.link : null,
    bounce_message: data.bounce ? data.bounce.message : null,
    event_at: payload.created_at,
    sent_at: data.created_at
  };
}

Filter Examples

Delivery Failures Only

json

{
  "name": "Delivery Failures",
  "logic": "or",
  "conditions": [
    {
      "field": "type",
      "operator": "equals",
      "value": "email.bounced"
    },
    {
      "field": "type",
      "operator": "equals",
      "value": "email.complained"
    }
  ]
}

Engagement Events

json

{
  "name": "Engagement Events",
  "logic": "or",
  "conditions": [
    {
      "field": "type",
      "operator": "equals",
      "value": "email.opened"
    },
    {
      "field": "type",
      "operator": "equals",
      "value": "email.clicked"
    }
  ]
}

Specific Sender

json

{
  "name": "Transactional Emails",
  "logic": "and",
  "conditions": [
    {
      "field": "data.from",
      "operator": "equals",
      "value": "[email protected]"
    }
  ]
}

Headers

Resend (Svix) webhooks include these headers:

Header	Description
`webhook-id`	Unique message identifier
`webhook-timestamp`	Unix timestamp (seconds)
`webhook-signature`	`v1,<base64-signature>`
`Content-Type`	`application/json`
`User-Agent`	`Svix-Webhooks`

Troubleshooting

Signature Verification Failed

Verify you're using the webhook signing secret (starts with whsec_)
Ensure verification type is set to svix, not hmac
Check that the secret matches what's shown in the Resend dashboard

Missing Events

Check which events are selected in Resend's webhook settings
Verify your sending domain is properly configured (SPF, DKIM)
Check Resend's webhook logs for delivery attempts

No Open/Click Events

Open and click tracking must be enabled in your Resend domain settings
HTML emails are required for tracking — plain text emails cannot be tracked
Some email clients block tracking pixels

Resend Integration ​

Setup ​

1. Create a Source in Hookbase ​

2. Configure Resend Webhook ​

3. Create Routes ​

Signature Verification ​

Timestamp Tolerance ​

Common Events ​

email.sent ​

email.delivered ​

email.opened ​

email.clicked ​

email.bounced ​

email.complained ​

Transform Examples ​

Slack Alert for Bounces and Complaints ​

Email Analytics Format ​

Filter Examples ​

Delivery Failures Only ​

Engagement Events ​

Specific Sender ​

Headers ​

Troubleshooting ​

Signature Verification Failed ​

Missing Events ​

No Open/Click Events ​

Resend Integration

Setup

1. Create a Source in Hookbase

2. Configure Resend Webhook

3. Create Routes

Signature Verification

Timestamp Tolerance

Common Events

email.sent

email.delivered

email.opened

email.clicked

email.bounced

email.complained

Transform Examples

Slack Alert for Bounces and Complaints

Email Analytics Format

Filter Examples

Delivery Failures Only

Engagement Events

Specific Sender

Headers

Troubleshooting

Signature Verification Failed

Missing Events

No Open/Click Events