Quick Comparison
| Zod | Yup | |
|---|---|---|
| TypeScript | First-class (infers types) | Supported but weaker |
| Bundle size | ~13KB | ~15KB |
| API style | Chainable, strict | Chainable, flexible |
| Type inference | z.infer<typeof schema> | Manual types needed |
| Ecosystem | Growing fast | Established |
When to Use Zod
- TypeScript projects (type inference is excellent)
- tRPC, React Hook Form, or Next.js Server Actions
- You want one source of truth for types and validation
- New projects
When to Use Yup
- Existing projects already using Yup
- Formik (built-in Yup integration)
- You prefer a more lenient validation style
Verdict
Zod for new TypeScript projects — the type inference alone makes it worth it. Yup if you’re already using it or need Formik integration.