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Overview

As part of the Slicker integration, you need to implement webhook endpoints that Slicker will call to deliver optimization decisions and dunning instructions to your billing system. All webhook events use a unified structure with a consistent envelope format.

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Implementation Requirements

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Endpoint Configuration

  • Protocol: HTTPS only (unencrypted HTTP is not supported)
  • Method: POST
  • URL: You define the webhook URL used for all event types and provide it to Slicker during integration setup
  • Content Type: application/json

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Authentication

Your webhooks must implement one of the following authentication methods to ensure that only Slicker can trigger events:

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Bearer Token Authentication

Authorization: Bearer YOUR_WEBHOOK_TOKEN
You’ll provide this token to Slicker during integration setup.

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Basic Authentication

Authorization: Basic base64(username:password)
You’ll provide the username and password to Slicker during integration setup.

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Unified Event Structure

All webhook events use a consistent envelope format: 
{
  "id": "evt_2uqkAo1bwllmzrgV2qtGv48DtGI",
  "type": "recovery_action",
  "created": "2023-01-18T09:00:00Z",
  "data": {
    // Event-specific fields
  }
}

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Common Fields

FieldTypeDescription
idstringUnique identifier for this webhook event
typestringEvent type identifier (e.g., recovery_action, pause_collection, complete_dunning)
createdstringISO 8601 timestamp of when the webhook was created
dataobjectEvent-specific payload that varies based on the event type

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Event Types

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Recovery Action Event

Sent when a payment should be retried: 
{
  "id": "evt_2uqkAo1bwllmzrgV2qtGv48DtGI",
  "type": "recovery_action",
  "created": "2023-01-18T09:00:00Z",
  "data": {
    "invoiceId": "inv_12345678",
    "subscriptionId": "sub_12345678",
    "actionSuggestion": "ACTION_SUGGESTION_RETRY",
    "idealRetryTime": "2023-01-18T09:30:00Z"
  }
}
Action Suggestion Values:
  • ACTION_SUGGESTION_RETRY: Attempt to process the payment again
  • ACTION_SUGGESTION_CARD_CHANGE: Request an updated payment method from the customer
  • ACTION_SUGGESTION_UNSPECIFIED: No specific action recommended

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Pause Invoice Collection Event

Sent when automatic retries should be paused. This is used during A/B tests to control which invoices should be retried by Slicker vs your system. 
{
  "id": "evt_3vrkBp2cxmmn0shW3ruHw59EuHJ",
  "type": "pause_collection",
  "created": "2023-01-18T10:00:00Z",
  "data": {
    "invoiceId": "inv_12345678"
  }
}

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Complete Dunning Event

Sent when dunning should be completed before the dunning period ends. 
{
  "id": "evt_4wslCq3dynn1ptiX4svIx60FvIK",
  "type": "complete_dunning",
  "created": "2023-01-18T11:00:00Z",
  "data": {
    "invoiceId": "inv_12345678"
  }
}

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Response Format

Your webhook should respond with a 200 OK status code and an optional JSON body if the event was successfully received: 
{
  "success": true,
  "message": "Event processed successfully"
}

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Implementation Best Practices

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Security

  • Use HTTPS with valid SSL certificates
  • Set up authentication with strong credentials
  • (Optional) Implement IP whitelisting (Slicker can provide IP ranges)

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Reliability

  • Acknowledge receipt quickly and process asynchronously
  • Implement idempotent processing based on event id to handle potential duplicate webhooks
  • Return appropriate error codes if requests can’t be processed
  • Slicker will retry failed webhooks, so ensure idempotency

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Monitoring

  • Set up alerts for failed webhook calls
  • Monitor webhook endpoint uptime

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Reference Documentation

For detailed API specifications, see:

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Support

If you need assistance with your webhook implementation:
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