Need a JSON Schema for a document you already have, or need to check whether a document actually matches one you've got? Do both in the same place, entirely in your browser.
Most free schema tools only go one direction: paste JSON, get a schema, and you're on your own from there. Json Web Viewer's Generate Schema (in the toolbar's More ⋯ menu) infers a JSON Schema from whatever document is in the panel and opens it in the other panel, ready to edit. Its counterpart, Validate Schema, then checks any document against that schema — or one you paste in yourself — and lists every place it fails, with a clear line drawn between "this isn't valid JSON" and "this is valid JSON that doesn't match the schema."
Nothing is uploaded either way — generation and validation both run entirely client-side.
Example — this JSON:
{
"id": 1,
"name": "Ada Lovelace",
"age": 36,
"active": true,
"tags": ["engineer", "mathematician"]
}generates a schema requiring an integer id, string name, and an array of strings for tags — open the example below and click Generate Schema to see the real output.
Open this example in the editor →
The link above pre-loads the person example above into Text mode in the left panel. Open
the More ⋯ menu in the toolbar and choose Generate Schema to infer a
schema into the right panel, or paste a schema of your own and choose Validate Schema… to
check this document against it.
No. Both schema generation and schema validation run entirely in your browser — your document and any schema you paste never leave the page.
Yes — that's the point of this page over a generator-only tool. Generate Schema infers a JSON Schema from your document into the other panel; Validate Schema then checks any document against that schema (or one you paste yourself) and lists exactly which parts fail and why.
Draft-07 and 2020-12, whichever the schema's own "$schema" field declares (defaulting to
draft-07 if it's absent).
Want a language type instead of a formal schema? See JSON to TypeScript (also generates Go and Rust).