Why is Zod so slow?

Zod, a popular TypeScript validation library, is renowned for its exceptional developer experience and robust type inference, but it faces criticism for performance issues, especially in high-throughput environments. This is primarily due to its architecture as a runtime interpreter, which, while offering flexibility and dynamic schema validation, incurs significant runtime costs compared to Ahead-of-Time (AOT) compiled libraries like Typia. Despite these performance drawbacks, Zod remains a practical choice for most web applications, where its validation speed is sufficient given the typical bottlenecks of network latency and database operations. However, for high-traffic systems where performance is critical, the solution lies in a build-time compilation approach that converts Zod schemas into JSON Schemas, subsequently using fast JSON Schema validators to create optimized functions for production use. This strategy allows developers to maintain Zod's user-friendly experience during development while achieving high performance in production, illustrating that understanding and addressing architectural trade-offs can optimize tools to meet varying demands.