Zod Schema Validation Patterns

Quick Guide: A schema is declared once and the TypeScript type derived from it with z.infer, so the rule and the type cannot drift. safeParse returns a result object where invalid input is expected and parse throws where it is a bug; refine and superRefine carry rules the built-in checks cannot express, and transform converts during validation — which splits z.input from z.output. On v4 the string formats moved to the top level (z.email(), z.url(), z.iso.*) and the v3 method chains are deprecated rather than removed; flatten(), format() and merge() have replacements, and reference.md carries the full migration list.

Detailed Resources:

• examples/core.md — schema definition, safe parsing, error formatting, unions, composition, async refinements
• examples/transforms.md — transforms, coercion, pipe chains, query params
• examples/advanced-patterns.md — branded types, .catch() fallbacks, readonly, recursive schemas
• reference.md — decision trees, method lookup, worked anti-patterns, v4 migration guide