JSON to Zod Schema
Convert JSON data into a Zod schema object for runtime validation in Next.js and tRPC projects.
What is the JSON to Zod Schema?
The JSON to Zod Schema converter turns a sample JSON object into a ready-to-use Zod schema for runtime validation in TypeScript projects. Paste your JSON, give the schema a name, and the tool generates a complete file with the import statement and an exported schema constant.
Zod is widely used in Next.js, tRPC, and form libraries to validate data at the boundaries of an application. Writing those schemas by hand is repetitive when you already have an example payload, so this tool infers the shape for you and outputs valid Zod code you can paste straight into your project.
The converter runs entirely in your browser. Your JSON is parsed locally with no signup and nothing is sent to a server, so it is safe to use with real API responses or sample data.
How to use the JSON to Zod Schema
- 1Enter a name for your schema in the Schema Name field, such as userSchema or apiResponse.
- 2Paste a representative JSON object or array into the JSON Input box.
- 3Click Generate Zod Schema to parse the JSON and produce the Zod code.
- 4Review the output, which includes the zod import and your exported schema constant.
- 5Click Copy to put the generated schema on your clipboard and paste it into your codebase.
What you can use it for
- Creating Zod schemas to validate fetch or API responses before using them in a Next.js app.
- Bootstrapping input validation for tRPC procedures or server actions from an example payload.
- Generating a starting schema for React Hook Form so form data is type-checked at runtime.
- Converting a JSON config file into a schema that catches malformed configuration early.
- Producing a quick schema draft during prototyping that you refine with stricter rules later.
Key features
- Infers z.string, z.number, z.boolean, z.null, and z.array types from the JSON values.
- Recursively handles nested objects and arrays to build z.object and z.array structures.
- Outputs a complete file with the zod import and a named export ready to paste.
- Reports invalid JSON with a clear error message instead of failing silently.
Frequently asked questions
How do I convert JSON to a Zod schema?
Paste your JSON object into the input box, set a schema name, and click Generate Zod Schema. The tool parses the JSON, infers a type for every field, and outputs a Zod schema you can copy directly into a TypeScript file.
Is the JSON to Zod Schema converter free?
Yes, it is completely free with no signup or account required. The conversion runs in your browser, so there are no usage limits and no data leaves your machine.
Does the tool detect optional or nullable fields?
It infers types from the values present in your sample JSON. A field with a null value becomes z.null, but the tool cannot know a field is optional from a single example, so you may need to add .optional() or .nullable() manually for fields that vary.
How are arrays handled in the generated Zod schema?
The tool inspects the first item of an array and generates z.array with that item's inferred type. Empty arrays become z.array(z.any()), so provide at least one representative element for an accurate schema.
Can I use the generated schema with tRPC or Next.js server actions?
Yes. The output is standard Zod code, so it works anywhere Zod is supported, including tRPC input validation, Next.js server actions, and form libraries. You may want to tighten the schema with constraints like .min() or .email() after generating it.
Is my JSON data sent to a server?
No. The JSON is parsed locally in your browser using JSON.parse and the schema is generated client-side. Nothing is uploaded, so you can safely paste real API responses.