JSON to Zod Schema
Generate Zod schemas and inferred TypeScript types from representative JSON.
What the JSON to Zod generator produces
The generator parses one JSON value and maps strings, numbers, integers, booleans, nulls, arrays, and objects to Zod expressions. The root name is normalized into a TypeScript-safe schema identifier. When inferred types are enabled, the output also includes a z.infer alias so the runtime validator and compile-time type come from the same schema.
Inference rules worth reviewing
- Integers become z.number().int(), while values containing a fractional part become z.number().
- Mixed array samples become unions. Arrays of objects merge observed keys and mark keys missing from any sample as optional.
- Optional format inference recognizes representative UUID, ISO date-time, email, and HTTP(S) URL strings with Zod string checks.
- Strict object mode appends .strict() so unknown keys are rejected instead of silently stripped by the generated object schemas.
- Empty arrays cannot reveal an element type and therefore become z.array(z.unknown()).
Sample inference is a starting point, not a contract
A sample cannot prove minimum lengths, numeric ranges, permitted enum values, cross-field rules, defaults, coercion behavior, or whether a field that happened to be present is always required. Compare the result with API documentation and real edge cases, then add Zod refinements and tests before accepting untrusted input. The tool generates source text only; it does not execute the schema or install Zod in your project.
Privacy and input limits
Generation is local and deterministic for the same options and input. Deeply nested input is capped to keep the browser responsive. Avoid pasting production tokens or personal data even into local tools when a sanitized payload can describe the same structure.
Related developer tools
Continue with JSON to TypeScript, JSON Schema Validator, JSON Formatter.
How to Use JSON to Zod Schema
- Paste a representative valid JSON object, array, or primitive value.
- Choose the schema name and whether to infer common string formats, use strict objects, and include a TypeScript alias.
- Generate the Zod source and review unions, optional fields, unknown arrays, and inferred formats.
- Copy the result, install the appropriate Zod version in your project, and add contract-specific constraints and tests.
Frequently Asked Questions
Can one JSON sample describe every valid payload?
- No. The generator can infer only the values and shapes present in the sample. Review required versus optional fields, business constraints, enums, defaults, refinements, and transformations against the real API contract.
How are arrays and missing object properties handled?
- Array element types are merged. Objects found in the same array share a combined shape, and a property missing from any sample object becomes optional. Mixed primitive arrays become Zod unions, while empty arrays use z.unknown() elements.
Is my JSON uploaded?
- No. JSON parsing and schema generation run in your browser. Sensitive data can still be exposed through clipboard history, browser extensions, screen sharing, or a shared device, so use sanitized examples when possible.
Sources & references
Primary references: Zod documentation; RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format; TypeScript Handbook: Object Types.
Review policy: references and behavior notes are checked whenever the tool implementation changes.