Trail of Bits is thrilled to announce the Testing Handbook, the shortest path for developers and security professionals to derive maximum value from the static and dynamic analysis tools we use at Trail of Bits. The chapter encapsulates the benefits and ideal use cases of Semgrep, offers instructions for initial setup, and provides a detailed look into tailoring rulesets for optimal security testing. It also includes a comprehensive guide to writing and testing custom rules, using the autofix feature, and optimizing Semgrep rules.