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API Basics

The Slicker API is a RESTful HTTP API that allows you to integrate your custom billing system with Slicker’s retry optimization and revenue recovery platform.
  • Protocol: HTTPS only (unencrypted HTTP is not supported)
  • Base URL: https://api.app.slickerhq.com
  • Data Format: All requests and responses use JSON format
  • Character Encoding: UTF-8

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Authentication

The API uses Bearer token authentication. You’ll receive an API key from Slicker which should be included in all API requests via the Authorization header: 
Authorization: Bearer YOUR_API_KEY
Your API key grants access to sensitive data and should be kept secure. Do not share your API key in publicly accessible areas such as GitHub, client-side code, or in API requests to other services.

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API Endpoints

Slicker’s custom billing API includes the following primary endpoints:
EndpointDescription
/v1/invoicesSend invoice data to Slicker
/v1/subscriptionsSend subscription data to Slicker
/v1/transactionsSend transaction data to Slicker
/v1/recovery_actionsRetrieve recommended recovery actions
Each endpoint accepts specific data formats as detailed in the API Reference.

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Request Limits

  • Maximum Batch Size: Each API request can contain up to 200 items (invoices, subscriptions, or transactions)
  • Rate Limiting: The API implements rate limiting to ensure stable performance for all users
  • Concurrency: We recommend no more than 5 concurrent requests per second
If you exceed these limits, the API will return a 429 Too Many Requests response. Implement appropriate backoff strategies in your integration.

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Best Practices

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Data Synchronization

  • Batching: Group related data in batches for more efficient processing
  • Frequency: Send data in real-time or near real-time for optimal recovery results
  • Completeness: Include as many optional fields as possible for better recovery strategies

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Error Handling

  • Implement retry logic with exponential backoff for failed requests
  • Log all API interactions for troubleshooting purposes
  • Monitor API responses for error patterns

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Testing

Before going live, thoroughly test your integration using:
  1. Historical data synchronization with the Slicker API
  2. Real-time event transmission
  3. Query for recovery actions

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API Versioning

The API version is included in the URL path (e.g., /v1/invoices). When new versions are released, we’ll provide appropriate migration guidance and timelines.

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Support

For API support or questions:

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Next Steps