Graphql To Zod Schema
GraphQL & Zod Toolchain

GraphQL SDL to Zod Validation Schema Generator

Convert GraphQL SDL types, queries, and inputs into runtime Zod validation schemas (z.object, z.string, z.array) with nullability handling.

100% Client-Side Privacy
Zero Server Transmission
Presets:
Strict Nullability Handling
GraphQL SDL Definition
import { z } from "zod";

// =========================================
// Custom Scalars
// =========================================

export const DateTimeSchema = z.string().datetime();
export type DateTime = z.infer<typeof DateTimeSchema>;

// =========================================
// Enums
// =========================================

export const CurrencySchema = z.enum(["USD", "EUR", "GBP", "JPY"]);
export type Currency = z.infer<typeof CurrencySchema>;

export const OrderStatusSchema = z.enum(["PENDING", "PROCESSING", "SHIPPED", "DELIVERED", "CANCELLED"]);
export type OrderStatus = z.infer<typeof OrderStatusSchema>;

// =========================================
// Object Types
// =========================================

export const UserSchema = z.object({
  id: z.string(),
  email: z.string(),
  fullName: z.string(),
  phoneNumber: z.string().nullish(),
  addresses: z.array(AddressSchema),
  primaryPaymentMethod: PaymentMethodSchema.nullish(),
  createdAt: z.string().datetime(),
});
export type User = z.infer<typeof UserSchema>;

export const AddressSchema = z.object({
  id: z.string(),
  street: z.string(),
  city: z.string(),
  postalCode: z.string(),
  countryCode: z.string(),
  isDefault: z.boolean(),
});
export type Address = z.infer<typeof AddressSchema>;

export const MoneySchema = z.object({
  amount: z.number(),
  currency: CurrencySchema,
});
export type Money = z.infer<typeof MoneySchema>;

export const PaymentMethodSchema = z.object({
  id: z.string(),
  type: z.string(),
  last4: z.string(),
  expMonth: z.number().int(),
  expYear: z.number().int(),
});
export type PaymentMethod = z.infer<typeof PaymentMethodSchema>;

export const OrderSchema = z.object({
  id: z.string(),
  orderNumber: z.string(),
  customer: UserSchema,
  status: OrderStatusSchema,
  total: MoneySchema,
  itemsCount: z.number().int(),
  createdAt: z.string().datetime(),
});
export type Order = z.infer<typeof OrderSchema>;

// =========================================
// Input Object Types
// =========================================

export const CheckoutInputSchema = z.object({
  userId: z.string(),
  shippingAddressId: z.string(),
  paymentMethodId: z.string(),
  notes: z.string().nullish(),
  couponCode: z.string().nullish(),
});
export type CheckoutInput = z.infer<typeof CheckoutInputSchema>;
Total GraphQL Types
9(5 types, 1 inputs)
Schema Fields
32
28 non-null • 4 nullable
Zod Schemas Created
v3.x Runtime Schema
Zero Dependencies

Zero-Knowledge Local Execution

All data processing, parsing, and compilation execute strictly inside your local browser memory. Zero external server uploads.

Sub-Millisecond AST Engine

All data payloads remain strictly local with zero external server communication.

Production Ready Export

Clean, optimized output formats ready for immediate deployment.

Technical Reference & Architecture Guide

GraphQL SDL to Zod Validation Schema Generator — Reference Guide

Convert GraphQL SDL types, queries, and inputs into runtime Zod validation schemas (z.object, z.string, z.array) with nullability handling.

Key Parameters & Controls

nullabilityModestring

Specifies how GraphQL nullable fields (fields without exclamation mark) are mapped to Zod: 'nullable' (.nullable()), 'optional' (.optional()), or 'nullish' (.nullish()).

Default: "nullable"
scalarMappingobject

Custom scalar dictionary mapping GraphQL scalars (e.g., DateTime, UUID, JSON, Decimal) to Zod validator expressions.

Default: { "DateTime": "z.string().datetime()", "UUID": "z.string().uuid()", "JSON": "z.record(z.any())" }
handleRecursionboolean

Wraps nested, self-referential, or mutually cyclical object references with z.lazy(() => Schema) to prevent circular dependency runtime crashes.

Default: true
generateInferredTypesboolean

Appends TypeScript type definitions inferred via z.infer<typeof Schema> for each generated schema export.

Default: true

Pro Tips & Best Practices

GraphQL schemas frequently feature

GraphQL schemas frequently feature recursive relations (such as User having posts and Post having an author User). When translating to Zod, always ensure recursive schemas evaluate lazily using z.lazy(() => TargetSchema) and define explicit return type annotations.

Map GraphQL 'input' types

Map GraphQL 'input' types to separate Zod schemas rather than 'type' definitions. Inputs in GraphQL often permit omitted fields (optional), while query return types distinguish strictly between explicit null and undefined.

If your API receives ISO

If your API receives ISO 8601 strings from JSON payloads but your business logic expects JavaScript Date instances, map custom scalar DateTime to z.coerce.date() or z.string().datetime() based on whether runtime mutation or strict string validation is required.

Common Gotchas & Troubleshooting

ReferenceError: Cannot access 'Schema' before initialization in circular GraphQL types

In JavaScript modules, hoisting does not resolve top-level const schema definitions referenced circularly. Enable 'handleRecursion' to wrap circular properties in z.lazy(() => RelatedSchema).

Custom scalars such as DateTime or JSON fallback to z.unknown() or fail runtime parsing

Add custom scalar definitions in the scalar mapping configuration. For example, map DateTime to z.string().datetime() and JSON to z.union([z.string(), z.number(), z.boolean(), z.record(z.any()), z.array(z.any())]).

Frequently Asked Questions

How are GraphQL nullable fields mapped to Zod validators?▼

In GraphQL SDL, fields are nullable by default unless marked with an exclamation mark (!). Non-null fields (String!) translate directly to primitive validators like z.string(). Standard nullable fields (String) translate to z.string().nullable(), or z.string().nullish() if nullabilityMode is set to allow undefined values.

Does this generator handle GraphQL Enums and Unions?▼

Yes. GraphQL enum declarations are transformed into z.enum(['VAL1', 'VAL2']) tuples or native TypeScript enum mappings. GraphQL union types (e.g., union SearchResult = User | Post) are converted into discriminated or structural Zod unions via z.union([UserSchema, PostSchema]).

Can I use generated Zod schemas in Apollo Server or tRPC resolvers?▼

Absolutely. You can import generated input schemas inside resolver arguments or mutation pipelines to validate incoming client arguments at the runtime network edge before executing internal database operations.

How are GraphQL list types ([Type], [Type!], [Type!]!) handled?▼

The generator preserves nested array nullability constraints: [String] becomes z.array(z.string().nullable()).nullable(), [String!] becomes z.array(z.string()).nullable(), and [String!]! becomes z.array(z.string()) with no null wrappers.

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