Why is z.email() showing as deprecated if not passed at the first place?

[codayon]

1. The line below, does not give any deprecation warning,

email: z.email("Invalid email format").string().trim().toLowerCase(),

And, if I hover email() in here, the LSP shows,

function email(params?: string | {
    abort?: boolean | undefined;
    pattern?: RegExp | undefined;
    error?: string | z.core.$ZodErrorMap<NonNullable<z.core.$ZodIssueInvalidType<unknown> | z.core.$ZodIssueInvalidStringFormat>> | undefined;
    message?: string | undefined | undefined;
} | undefined): z.ZodEmail

2. But this line gives a deprecation warning,

email: z.string().trim().toLowerCase().email("Invalid email format"),

And, if I hover email() in here, the LSP shows,

'(params?: string | { abort?: boolean | undefined; pattern?: RegExp | undefined; error?: string | $ZodErrorMap<$ZodIssueInvalidStringFormat> | undefined; message?: string | undefined; } | undefined): ZodString' is deprecated.

(method) ZodString.email(params?: string | {
    abort?: boolean | undefined;
    pattern?: RegExp | undefined;
    error?: string | z.core.$ZodErrorMap<z.core.$ZodIssueInvalidStringFormat> | undefined;
    message?: string | undefined | undefined;
} | undefined): z.ZodString
@deprecated — Use z.email() instead.

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For context, I was trying out zod validation for my auth route, and this is from validations/auth.js,

import * as z from "zod";

const SignUpSchema = z.object({
  name: z
    .string()
    .min(2, "Name must be at least 2 characters")
    .max(50, "Name cannot be more than 50 characters")
    .trim(),
  email: z.string().trim().toLowerCase().email("Invalid email format"),
});

[dosubot[bot]]

Hi @codayon! I'm Dosu and I’m helping the zod team.

This is expected in Zod v4: the chainable .email() method on z.string() is deprecated and will show a warning, while the top-level z.email() function is the new, preferred way to validate emails and does not show a deprecation warning. This change was made because string format validations like email, uuid, etc., are now represented as specialized subclasses (like ZodEmail) and exposed as top-level factory functions for better tree-shaking and API clarity. The old method form (z.string().email()) still works but is marked as deprecated in TypeScript/JSDoc to encourage migration to the new API (changelog, docs).

If you want to combine string transformations (like .trim() or .toLowerCase()) with email validation, the recommended pattern is:

z.string().trim().toLowerCase().pipe(z.email())

or

z.preprocess(val => val.trim(), z.email().toLowerCase())

This approach preserves transformation order and uses the new z.email() schema as intended (maintainer comment).

Let me know if this answers your question—feel free to close the issue if you're all set!

To reply, just mention @dosu.

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