PaySimple

**Stripe** is a financial technology company that provides online payment processing software and APIs for businesses of all sizes. Founded in 2010 by Irish brothers Patrick and John Collison, it lets companies accept payments, manage subscriptions and billing, handle tax compliance, prevent fraud, and access treasury and banking tools. Headquartered in South San Francisco and Dublin, it remains privately held.

Polar is a billing platform and Merchant of Record aimed at developers building AI-era software. It provides payments, subscriptions, and usage-based billing while handling global tax and compliance for its customers.

PayPal Enterprise Payments, formerly Braintree, provides tokenization and payment processing for transactions initiated by AI agents. Merchants receive constrained payment tokens and continue using standard charging, settlement, refund, chargeback, risk, and compliance workflows; the tokens can be limited by merchant, amount, currency, and expiry so card details remain outside the agent and the merchant's PCI scope. The service supports agentic-commerce integrations including Instant Checkout in ChatGPT through the Agentic Commerce Protocol, Google AI Mode through the Universal Commerce Protocol and Google Pay, and MCP apps that either provide an in-agent checkout interface or hand off to an external checkout page.

Google Pay is a mobile payment service used for contactless payments. The videos describe it as relying on secure device hardware so that some payment processing can occur before transactions reach the card networks.

Square is a financial services and mobile payments company founded in 2009 and now a business unit of Block, Inc. It offers payment processing hardware and software, point-of-sale systems, online payments, payroll, and small-business services such as lending and inventory management.