APIs (Application Programming Interfaces) enable integration and automation across different vendor platforms within a SOAR (Security Orchestration, Automation, and Response) solution. They allow security tools to communicate and execute automated actions, making them essential for orchestrating responses across diverse systems and platforms. While STIX/TAXII provides standards for threat information sharing, and data enrichment enhances context, APIs are the primary means of enabling cross-platform automation, as recommended in CompTIA CySA+ materials on SOAR operations.