card-iso8583

What problem does it solve?

ISO8583 is the global standard for payment card message exchange, enabling authorization decisions in milliseconds. This skill covers message structure (MTI + bitmap + data elements), building authorization requests (0100) with PAN/track data/amount/merchant info, parsing network responses (0110) with approval codes and response codes, high-performance TCP socket gateways for Visa/Mastercard networks, real-time authorization decision engine with velocity checks and fraud scoring, stand-in authorization for offline mode, and clearing/settlement file processing for post-transaction reconciliation.

Core Features & Use Cases

• IsoMessageBuilder constructs ISO 8583 0100 authorization requests with proper bitmap encoding and field formatting.
• CardAuthorizationService implements the authorization decision logic with velocity checks, fraud scoring, and account validation.
• TcpSocketGateway manages pooled NIO socket connections to Visa/Mastercard networks with heartbeat monitoring.

Quick Start

Run a sample authorization request against test network endpoints using a test PAN, amount, and merchant to observe the ISO 8583 flow.