Handling Missing Values in Zod
From the Zod cheat sheet · Optional, Nullable, Default & Catch · verified Jul 2026
Handling Missing Values
Optional, nullable, default values, and catch fallbacks
typescript
z.string().optional(); // string | undefined
z.string().nullable(); // string | null
z.string().nullish(); // string | null | undefined
z.string().default("hello");
z.string().catch("fallback");💡 .default() only kicks in when the value is undefined, not null
⚡ .catch() is like a try/catch — it swallows ALL errors and returns the fallback
📌 Use .nullish() for fields that may be null OR undefined (common in databases)
🟢 .default() with a function generates a fresh value on every parse — ideal for IDs
optionalnullabledefault