Integrating Paddle with Slack for Real-Time Subscription Alerts

Comparison matrix

ROI metrics

Automating real-time transaction notifications eliminates manual dashboard export and cross-team status requests, generating full payback in less than 4 weeks for a 10-person operation.

Step-by-step setup guide

1. 1.Create a Slack App and Enable Incoming Webhooks

   Open the Slack API dashboard at api.slack.com/apps, create an app in your target workspace, activate Incoming Webhooks, and generate a webhook URL assigned to #sales-notifications.

   https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX

2. 2.Configure Paddle Notification Destination

   Navigate to Paddle Dashboard > Developer Tools > Notifications. Add a new Webhook destination pointing to your intermediate endpoint (e.g., AWS Lambda, Cloudflare Worker, or backend service) and select the 'transaction.completed' event. Note the secret key starting with 'pdl_ntf_set_'.

   curl -X POST https://api.paddle.com/notification-settings \
     -H 'Authorization: Bearer YOUR_PADDLE_API_KEY' \
     -H 'Content-Type: application/json' \
     -d '{"description":"Slack Subscription Sync","destination":"https://api.example.com/webhooks/paddle","subscribed_events":[{"event_type_name":"transaction.completed"}]}'

3. 3.Verify Paddle Webhook Signatures

   Paddle delivers the signature in the Paddle-Signature header formatted as ts=TIMESTAMP;h1=HASH. Compute an HMAC-SHA256 digest of TIMESTAMP:RAW_BODY using your notification secret and compare hashes using a constant-time comparison algorithm.

   const crypto = require('crypto');
   function verifyPaddleSignature(rawBody, signatureHeader, secret) {
     const parts = Object.fromEntries(signatureHeader.split(';').map(p => p.split('=')));
     const expectedHash = crypto.createHmac('sha256', secret).update(`${parts.ts}:${rawBody}`).digest('hex');
     return crypto.timingSafeEqual(Buffer.from(parts.h1), Buffer.from(expectedHash));
   }

4. 4.Construct Slack Block Kit Payload

   Extract customer email, transaction value, currency, and product title from the verified transaction.completed payload. Assemble a JSON payload matching Slack's Block Kit specifications for structured rendering.

   {
     "blocks": [
       {
         "type": "header",
         "text": {"type": "plain_text", "text": "🎉 New Subscription Activated"}
       },
       {
         "type": "section",
         "fields": [
           {"type": "mrkdwn", "text": "*Customer:*\nuser@example.com"},
           {"type": "mrkdwn", "text": "*Amount:*\n$99.00 USD"},
           {"type": "mrkdwn", "text": "*Plan:*\nPro Tier (Annual)"},
           {"type": "mrkdwn", "text": "*Status:*\nCompleted"}
         ]
       }
     ]
   }

5. 5.Dispatch Message to Slack Webhook

   Send an HTTP POST request carrying the Block Kit JSON structure to the Slack Incoming Webhook URL saved in Step 1. Ensure the request headers include Content-Type: application/json and process HTTP 200 responses.

   curl -X POST https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX \
     -H 'Content-Type: application/json' \
     -d '{"text":"New payment: $99.00 USD from user@example.com"}'

Webhook payload example

{
  "event_id": "evt_01h8b61c9g2n82p2wqmfxr1y1z",
  "event_type": "transaction.completed",
  "occurred_at": "2024-03-24T14:32:01.120Z",
  "data": {
    "id": "txn_01h8b61bwz13v1191s8e3rkg10",
    "status": "completed",
    "customer_id": "ctm_01h8b5x8b3g20857q2245b9p12",
    "currency_code": "USD",
    "details": {
      "totals": {
        "subtotal": "9900",
        "tax": "0",
        "total": "9900"
      },
      "line_items": [
        {
          "price": {
            "id": "pri_01h8b5v4j44k6h7803d3z1a9f0",
            "description": "Team Plan Monthly",
            "unit_price": {
              "amount": "9900",
              "currency_code": "USD"
            }
          },
          "quantity": 1
        }
      ]
    },
    "payments": [
      {
        "payment_method_id": "pm_01h8b61b36v518v9vbfn2a1e09",
        "amount": "9900",
        "status": "captured"
      }
    ]
  }
}

FAQ