The answer
z.string().email(). Zod validates the format. For stronger validation, you can chain .refine with a custom check (e.g., block disposable email providers).
How to Write an Express Validation Middleware With Zod
How do I validate an email in Zod?
More FAQs in How to Write an Express Validation Middleware With Zod
Define a Zod schema, write a validate(schema) middleware factory that uses safeParse, returns 400 with errors if invalid, replaces req.body with parsed data if valid, and calls next. Apply per route: router.post('/signup', validate(signupSchema), signup).
TypeScript inference, great error messages, composable schemas, safe parse (returns success or error instead of throwing), and built-in types. It is one of the best modern validators for Node.js.
Same pattern, but validate req.params. Example: const idSchema = z.object({ id: z.string().length(24) }); router.get('/users/:id', validateParams(idSchema), getUser). Use a separate factory that reads req.params.
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