Combining Schemas in Zod
From the Zod cheat sheet · Unions, Intersections & Discriminated Unions · verified Jul 2026
Combining Schemas
Union, intersection, and discriminated union patterns
typescript
// Union (any of)
const StringOrNumber = z.union([z.string(), z.number()]);
// or: z.string().or(z.number())
// Discriminated union (faster, better errors)
const Shape = z.discriminatedUnion("kind", [
z.object({ kind: z.literal("circle"), radius: z.number() }),
z.object({ kind: z.literal("square"), size: z.number() }),
]);💡 Use discriminatedUnion when objects share a common literal field — much faster than union
⚡ Discriminated unions give clearer error messages by checking only the matching variant
📌 Prefer .extend() over intersection for combining object schemas — same result, cleaner
🟢 z.union() tries each schema in order — first match wins
unionintersectiondiscriminated