Understand the importance of ensuring SLA performance and functional reliability for business-critical APIs in today's digital landscape where over a billion more mobile devices are projected to become connected. API load testing and uptime or ping monitors have traditionally been relied upon, but these methods often fail to reveal issues that arise due to inconsistent or unexpected traffic patterns. Instead, true API performance monitoring is necessary to evaluate how well APIs perform under different conditions, including functional API testing, API latency or speed testing, and API behavior under varying request rates. API load testing can be complex and includes types such as standard load testing, stress testing, spike testing, and soak testing, which may not detect issues that arise due to prolonged periods of high load. Combining API functional tests with performance tests can simplify the overall API testing strategy by reusing functional tests as load tests, allowing for a more nuanced understanding of how APIs handle different load patterns. Ultimately, SRE teams should adopt this approach to increase confidence in production and live environments, expand visibility across the SDLC, and drive continuous improvement through global insights and historic performance trends.