Integrating Cybersource API with your website or app is straightforward. First, create a Cybersource developer account to access sandbox testing and get your API credentials (Merchant ID, API key, and secret key). Choose the APIs you need, such as Payments for processing cards, Fraud Management for security, or Subscription API for recurring billing. You can integrate using REST APIs, SOAP APIs, or official SDKs in languages like Java, Python, PHP, or Node.js. Start in the sandbox to test transactions, handle approvals, declines, and fraud reviews, and ensure your payment flows work correctly. Always use HTTPS, avoid storing raw card data, and leverage tokenization to stay PCI compliant. Once testing is complete, switch to live credentials and monitor transactions. Following these steps ensures a secure, reliable, and efficient payment integration for your website or app.