TypeScript Zod v4 Practices

Framework-independent Zod 4 validation and contract rules. Read the relevant atomic card in references/.

When to Apply

• Write, review, or refactor Zod 4 schemas.
• Validate external APIs, forms, environment variables, or payloads.
• Choose parsing behavior, model transforms, refinements, unions, or nullability.
• Organize contracts shared between modules, applications, and persistence.

Rule Categories by Priority