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Schema helper

JSON to Zod schema

Paste JSON and instantly generate a Zod schema with inferred shapes.
Objects and arrays are inspected to choose the right validators and unions,
so you can reuse the schema for parsing or runtime validation.

Everything runs locally in your browser—no data is sent anywhere.

Guide: How to use & features

  • Paste JSON into the input and click “Convert to Zod.”
  • Objects are formatted into `z.object({...})` blocks with nested schemas.
  • Arrays infer their element types; mixed values are wrapped with `z.union([...])`.
  • Use the copy or clear buttons to reuse the schema or start over.

Samples: Sample input & output

Convert JSON to Zod schema

Input

{"id":42,"enabled":false,"labels":["alpha","beta"]}

Output

const Schema = z.object({
    id: z.number(),
    enabled: z.boolean(),
    labels: z.array(z.string()),
});

FAQ: FAQ

  • What is the Zod schema useful for?

    Use it to validate, at runtime, that data coming from outside — API responses, form input — matches the shape you expect. Calling .parse() with the generated schema catches mismatched values early, and you can also derive the TypeScript type with z.infer.

  • Are optional and nullable applied correctly?

    Types are inferred from the sample you paste, so keys that are always present become required. Add .optional() to fields that may be omitted and .nullable() to fields that allow null after generation to match your real data.

  • What happens when an array mixes several types?

    Mixed elements are built into a z.union([...]). If the union is wider than intended, regenerate from a narrowed sample or adjust it by hand to the types you need.

Use cases: Common use cases

  • Drafting form validation

    Generate Zod schemas from backend examples and drop them into front-end validation logic immediately.

  • Verifying mock data

    Parse local mock JSON with Zod to catch unexpected fields or shapes at runtime.

  • Sharing schema fragments

    Copy generated snippets to reuse across libraries and keep runtime checks aligned with types.

Notes: Notes & limitations

  • Work stays in your browser

    Inputs and outputs remain local. Closing the tab or clearing cache will remove any temporary state.

  • Validate critical data

    Results are helper outputs—double-check them before sending to production systems or sharing externally.

  • Large payloads depend on your device

    Very large text or files can feel slow in some browsers. Use a desktop environment for heavy workloads.

JSON Response to Zod Schema Converter

Accept any unverified JSON data and instantly output schema validation code for “Zod”—the industry-standard runtime validation library inside the TypeScript ecosystem.
When simultaneously attempting to enforce both validation logic and static typing upon dynamic data returned from an API, manually authoring Zod schemas can be extraordinarily labor-intensive. By directly converting expected JSON formats into Zod objects, you can build type-safe, resilient applications more effortlessly.

When it helps

  • Validate external APIs: Build a first-pass Zod schema from a real JSON response.
  • Protect runtime boundaries: Check data coming from webhooks, forms, storage, or third-party services.
  • Create test fixtures: Generate schemas while documenting expected payload shapes.

Inference note

The generated schema reflects the sample JSON, not every possible response. Review optional fields, nullable values, enums, arrays with mixed shapes, and nested objects before using the schema in production validation.

Articles for this tool

Introduction
2026-01-11

Simplify JSON Validation with Zod

Learn how to automate runtime validation and type generation for JSON data using Zod, a TypeScript-friendly schema definition library.

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JSON Formatting and Validation: How to Read API Responses Safely

Learn how to format JSON, catch syntax errors, inspect value types, and turn API responses into types, schemas, or documentation.

Introduction
2026-02-16

The JSON Ecosystem: Connecting Formatting, Types, Validation, and API Specs

Follow one API response through formatting, TypeScript types, Zod runtime validation, and OpenAPI definitions—with real code at every step—for a clear view of type-safe API development.

Recent Articles

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A cross-database CREATE TABLE (DDL) reference with cheat sheets for data types, auto-increment keys (AUTO_INCREMENT / IDENTITY / rowid), foreign key ON DELETE behavior, and the CHECK constraint that MySQL silently ignores.

Introduction
2026-08-03

How CREATE TABLE Generation From a Visual Table Design Works | DDL Builder

A look inside DDL Builder, which turns a visually designed table into CREATE TABLE statements and an ER diagram. Covers the MySQL/PostgreSQL/SQLite type-mapping rules and the column-inference algorithm used for JSON samples.

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GitHub Actions needs Design Patterns: Speed Up CI, Avoid the Anti-Patterns

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A reference for SQL JOIN types (INNER/LEFT/RIGHT/FULL/CROSS/SELF) with a cheat sheet and row-count walkthroughs. Covers why one-to-many joins duplicate rows, the WHERE-vs-ON NULL trap, and how to write multi-table joins.

Introduction
2026-07-16

Case Converter: camelCase, snake_case & kebab-case — 9 Styles at Once

Convert identifiers between camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case and more — all nine styles side by side. Handles acronym runs like HTTPServer, digits, and bulk multi-line conversion.

Introduction
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LLM API Cost Calculator: Compare Claude, GPT & Gemini Pricing Side by Side

Paste a prompt, set the expected output tokens, and compare per-request API costs across Claude, GPT and Gemini models. Covers input/output pricing structure, auto-updated price tables, and estimate limits.

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