The JavaScript runtime evolution has led to competition between Node.js, Deno, and Bun, each offering unique features.Architectural breakdown reveals Node.js with CommonJS legacy, Deno with secure TypeScript runtime, and Bun as an all-in-one runtime.Performance benchmarks show Bun outperforming Node.js and Deno in HTTP throughput, with faster filesystem operations.Feature comparison highlights TypeScript support, package management, web compatibility, and security models across the three runtimes.