Build customized solutions that accept payments (online, in-person, or in-app), manage products and customers, and handle the day-to-day operations that keep business running. Square APIs are powerful, secure, reliable, and free to use. Square APIs enable you to accept payments securely and integrate your app with Square’s first party product ecosystem. Build full-featured business apps for yourself or millions of Square sellers. Our API Reference is organized around core business workflows: taking payments, managing orders, syncing items and inventory with Square Point of Sale, creating customer records, managing business locations, and enabling Square sellers to use your app. Connect your app to our secure and PCI-compliant platform to accept payments in person, in an app, or online. Take orders via web and mobile applications and send them directly to Square Point of Sale or your own custom application. Enable fast and flexible catalog management, including individual and batch support for retrieval, updates, and deletion. Leverage customer data to create applications that help sellers grow their sales and build customer loyalty. Make better supply chain decisions by creating tools to improve inventory management. Integrate timekeeping or collaboration tools that support sellers and help maintain their high performing teams.