Old Tom Bombadil is a merry fuzzer! | Oskar Wickström | Bug Bash 2026

Oskar Wickström created Bombadil, a new property-based testing framework designed specifically for web applications that runs in real browsers. In this talk at Bug Bash, he explains how Bombadil allows developers to write specifications in TypeScript or JavaScript using three main components: properties (logical statements about app correctness), extractors (functions that capture browser state), and generators (that produce action trees for testing). The framework can test applications automatically using default properties and actions, or developers can write custom specifications. When violations are found, Bombadil provides detailed explanations and includes an inspection UI for debugging. http://antithesis.com/