Kulipa .NET Client Library

C# .NET client library for integrating with the Kulipa crypto-based payment card API.

Overview

This library abstracts low-level HTTP communication, authentication, and request/response handling into a reusable SDK, enabling developers to build reliable financial applications faster with C# and .NET 8.0+.

Key Features

📋 Resource-Based Architecture

• Users Management - Create and manage user accounts with KYC support
• Card Operations - Issue, manage, and control payment cards
• Wallet Management - Handle crypto wallets, top-ups, and withdrawals
• Card Payments - Track and manage card payment transactions
• Webhooks - Secure webhook signature verification with ECDSA

🛡️ Security & Reliability

• API Key Authentication - Secure authentication with configurable API keys
• Idempotency Support - Built-in idempotency for POST/PUT operations
• Rate Limiting - Intelligent rate limit handling with backoff strategies
• Retry Policies - Configurable retry logic with exponential backoff
• Circuit Breaker - Resilient HTTP clients using Polly

🔧 Developer Experience

• Dependency Injection - Full integration with Microsoft.Extensions.DependencyInjection
• Strongly Typed Models - Complete type safety for all API operations
• Comprehensive Error Handling - Custom exception hierarchy for different HTTP status codes
• XML Documentation - Complete IntelliSense support
• Async/Await Support - Modern asynchronous programming patterns

Requirements

• .NET 8.0 or later
• Secure storage of API keys and secrets (not hardcoded, not logged)

Installation

dotnet add package Kulipa.Sdk

Quick Start

  // Register services
  services.AddKulipaSdk(options =>
  {
      options.ApiKey = "your-api-key";
      options.Environment = KulipaEnvironment.Sandbox;
  });

  // Use the client
  public class PaymentService
  {
      private readonly IKulipaClient _kulipaClient;

      public PaymentService(IKulipaClient kulipaClient)
      {
          _kulipaClient = kulipaClient;
      }

      public async Task CreateUser()
      {
          var user = await _kulipaClient.Users.CreateAsync(new CreateUserRequest
          {
              // User details
          });
      }
  }

Testing Support

The SDK is built with testing in mind:

• MSTest framework with FluentAssertions
• Moq for dependency mocking
• Comprehensive unit and integration test coverage
• Test utilities for webhook signature verification

Development Guidelines

• Architecture: Clean architecture, SOLID principles
• Error Handling: Timeouts, retries, and structured exceptions
• Testing: Unit + integration tests with mocks for API responses
• Docs: XML documentation, examples, alignment with official API docs
• Versioning: Semantic versioning (SemVer)
• Distribution: Published via NuGet with release notes

Contributing

Contributions are welcome. Please follow the repository’s coding standards and submit pull requests with tests included.

License

This SDK is licensed under an Apache-2.0 license. See the LICENSE file for details.

Support

For questions, issues, or feature requests, please:

• Open an issue on GitHub
• Check the API documentation
• Review the SDK documentation

Reference

• NuGet Package: https://www.nuget.org/packages/Kulipa.Sdk
• API Documentation: https://kulipa.readme.io/reference/