JSON Schema Generator

Infer a JSON Schema (draft 2020-12) from a JSON sample

🔒 100 % in-browser🆓 Gratuit pour toujours⚡ Pas de signup
Note : L'interface de l'outil ci-dessous n'est actuellement disponible qu'en anglais. On traduit les UI une par une. Voir cet outil en anglais →

Ideal for LLM structured output (OpenAI/Anthropic tool calling), API validation with ajv, or documenting a payload. All fields in the sample are marked required - remove any that are optional.

Comment ça marche

  1. 1
    Paste a JSON sample

    Drop a representative object or array - an API response, a config, an LLM function call payload.

  2. 2
    Name the root type

    Give the schema a title (defaults to 'RootSchema'). Used by generators and error messages.

  3. 3
    Copy the schema

    Paste directly into your LLM tool definition, ajv, or API docs.

À propos de JSON Schema Generator

Free online JSON Schema generator. Paste a JSON sample to instantly get a draft-2020-12 JSON Schema with types, required fields, and nested object/array shapes. Ideal for LLM structured output (OpenAI/Anthropic tool calling), ajv validation, and API contracts. JSON Schema Generator sur 712 Tools tourne entièrement dans ton browser via des APIs JavaScript natives - aucun server ne voit jamais tes données. Résultats instantanés, privacy complète, et aucune limite d'upload.

Que ce soit pour une session de debug, un sanity check rapide ou un incident en prod, cet outil est gratuit à utiliser autant que tu veux. Pas de watermarks, pas de signup et pas d'ads dans l'outil.

Questions fréquentes

Which JSON Schema draft?

Draft 2020-12 - the current version, and what OpenAI and Anthropic expect for structured output / tool calling.

Are all fields marked required?

Yes - every field in your sample. Remove the ones that are conditional from the required array by hand.

How are arrays typed?

The tool merges all items and produces one items schema. Mixed arrays become a union of types.

Is my JSON sent anywhere?

No. Inference happens entirely in your browser.

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