ISL Module Central1 is a multi-cloud payment processor abstraction layer that decouples business logic from Central One API integration through dependency injection and service interfaces. The architecture routes payment, customer, and contact processing requests through a Central1Client that manages authentication via ITokenService, request signing via ISignatureService, and HTTP communication via IHttpSender, with distributed token caching in Redis. This modular design enables teams to swap implementations (Azure KeyVault, AWS KeyVault) without changing consumer code, following SOLID principles and supporting both circuit-breaker-only and circuit-breaker-with-retry resilience patterns. Fork this diagram on Diagrams.so to customize service implementations, add additional processors, or adapt the pattern for other third-party APIs. The architecture deliberately keeps Central-One-specific logic isolated, making it a template for building similar payment gateway integrations across AWS, Azure, or hybrid environments.