Zod Validation Utilities

Zod Validation Utilities

Overview

Production-ready Zod v4 patterns for reusable, type-safe validation with minimal boilerplate. Focuses on modern APIs, predictable error handling, and form integration.

When to Use

• Defining request/response validation schemas in TypeScript services
• Parsing untrusted input from APIs, forms, env vars, or external systems
• Standardizing coercion, transforms, and cross-field validation
• Building reusable schema utilities across teams
• Integrating React Hook Form with Zod using zodResolver

Instructions

1. Start with strict object schemas and explicit field constraints
2. Prefer modern Zod v4 APIs and the error option for error messages
3. Use coercion at boundaries (z.coerce.*) when input types are uncertain
4. Keep business invariants in refine/superRefine close to schema definitions
5. Export both schema and inferred types (z.input/z.output) for consistency
6. Reuse utility schemas (email, id, dates, pagination) to reduce duplication

Validation Workflow

When integrating validation into an API handler or service: