Fees: Evaluate the transaction fees, setup fees, and monthly fees. Some processors may also charge for refunds and chargebacks. Security: Ensure the processor complies with PCI-DSS standards to protect customer data. Integration: The processor should seamlessly integrate with your e-commerce platform or point-of-sale system. Customer Support: Reliable customer service is essential for resolving issues promptly. Global Reach: If your business is international, choose a processor that supports multiple currencies and languages.