Zod vs Yup vs Valibot

Code examples

const UserSchema = z.object({
  id: z.string().uuid(),
  email: z.string().email(),
  role: z.enum(["admin", "member"]),
});

const result = UserSchema.safeParse(payload);

if (!result.success) {
  return Response.json(
    { error: "Invalid request", issues: result.error.flatten().fieldErrors },
    { status: 400 },
  );
}

return Response.json({ user: result.data });

When to choose Zod

Choose Zod when validation lives in TypeScript application code and you want schemas, parsing, error handling, and inferred types in one place.

• API responses and request bodies.
• Next.js route handlers and server actions.
• Shared schemas between client and server code.
• JSON-to-schema workflows where the output should be copied into TypeScript.

When Yup still makes sense

Yup still makes sense when an existing form stack already uses it and the migration cost is not justified. For new TypeScript-first API validation, Zod usually provides clearer type inference and parsing ergonomics.

When Valibot is attractive

Valibot is attractive for bundle-sensitive clients and teams that prefer small, composable validator functions. Review ecosystem fit, examples, and team familiarity before choosing it for API boundaries.

API validation comparison

API validation usually cares more about runtime parsing, precise error handling, and inferred output types than form-only ergonomics. That is why Zod often fits API boundaries better than form-first libraries.

Server actions and route handlers

In server actions and route handlers, prefer validators that make invalid input a controlled branch. Zod's `safeParse` result is a good fit for returning structured 400 responses or field errors.

Bundle and runtime tradeoffs

For browser-heavy forms, bundle size can matter. For server-side API validation, readability, schema ownership, and error observability often matter more than a few kilobytes.

• Use Zod when type inference and app-boundary parsing are the priority.
• Use Valibot when bundle budget is the main constraint.
• Use Yup when existing form code already depends on Yup and migration risk is high.

Decision path

Start with JSON to Zod Converter when you need a browser-first workflow with copy-ready TypeScript output. Choose Yup and Valibot when its tradeoffs match your team better.

FAQ

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