JSON to Zod Schema Converter

Zod is the de-facto validation library of the TypeScript ecosystem: you define a schema once and get both runtime validation and a static type from the same source of truth. The tedious part is writing that schema by hand when the shape already exists as JSON — an API response you just received, a config file, a database row. This converter does the transcription for you: paste JSON, get a ready-to-import Zod schema plus a z.infer type export.

It goes beyond a mechanical one-to-one mapping. String values are inspected and, when they match, emitted as the stricter Zod validators — z.email(), z.uuid(), z.url(), and z.iso.datetime() for ISO 8601 timestamps — so the generated schema actually validates instead of accepting any string. Format inference is conservative: if the samples in an array disagree, it falls back to plain z.string() rather than guessing. You can switch inference off entirely when you want the loosest schema.

Arrays of objects get real shape merging. Every element is examined, and a key that appears in some elements but not others is marked .optional() — the detail hand-written schemas most often get wrong, and one that single-element converters cannot see at all. Mixed-type arrays become z.union(), null-and-value mixes become .nullable(), whole-number samples become z.number().int(), and non-identifier keys are quoted correctly.

The output targets Zod v4 by default, using the current top-level validator style, with a one-click switch to classic v3 chains for older codebases. Everything runs entirely in your browser — your payloads, which often contain real user data, never leave your device. Paste, copy, and keep the schema as the single source of truth it was meant to be.