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AI JSON Prompt Generator

Get machine-readable answers from a language model. Describe the task and list the fields you want with their type and description – strings, numbers, booleans, enums, arrays, optional values. The generator builds a JSON Schema (draft 2020-12), a prompt that tells the model to return exactly one object matching it, with null for missing values and no extra keys, and an example of the expected shape.

  • Runs in your browser
  • No sign-up
  • Free to use
Start from an example

Types: string, number, integer, boolean, enum(a,b,c), array<string>, array<number>, object. Add “?” after the type for optional fields.

    How to use AI JSON Prompt Generator

    1. Describe the extraction or generation task.
    2. List fields: name | type | description.
    3. Choose prompt, schema or example output.
    4. Use the prompt or schema in your API call.

    AI JSON Prompt Generator features

    JSON Schema

    Draft 2020-12.

    Enums and arrays

    Typed fields.

    Optional fields

    With “?”.

    Strict mode

    No extra keys.

    Example output

    Expected shape.

    Private

    Built in your browser; nothing is sent to an AI service.

    When to use AI JSON Prompt Generator

    • Extracting data from emails and documents.
    • Classifying support tickets.
    • Feeding AI output into apps.
    • Building data pipelines.

    AI JSON Prompt Generator FAQ

    Do I still need validation?

    Yes. Validate every answer against the schema before using it; models can still make mistakes.

    Can APIs enforce the schema?

    Many offer structured outputs or JSON mode that accept a schema; the prompt helps either way.

    Why null instead of guessing?

    Guessed values look real and are hard to spot; null makes missing data explicit.

    Which types are supported?

    string, number, integer, boolean, object, enum(a,b) and arrays of simple types.

    JSON Schema Validator Paste a JSON Schema and a JSON document and see at once whether the data conforms.… AI Prompt Generator Turn a rough idea into a prompt that gets useful answers the first time. Describe… JSON Formatter Paste messy or minified JSON and get clean, indented output instantly. Errors are… Prompt Template Generator Make a prompt that worked once reusable. Paste the concrete prompt and list the…

    Reliable structured output

    Free-text answers are hard to process automatically. A schema with clear field descriptions tells the model exactly what to produce and lets your code check the result.

    Field descriptions matter: “ISO date YYYY-MM-DD” leaves far less room for interpretation than “date”.

    This tool does not call an AI model. It turns your answers into a well-structured prompt in your browser, so it costs nothing, works offline once loaded and never sends your text anywhere. Paste the result into ChatGPT, Claude, Gemini, Copilot or any other assistant, or into the system message of an API call.

    Good prompts are specific about the task, the context the model cannot know, the audience and the shape of the answer. The fields on this page cover exactly those parts; leave optional fields empty when they do not apply, and the prompt stays short.

    Review the answer you get: language models can be confidently wrong, especially about facts, numbers, names and recent events. Ask for sources or mark claims to check, and keep personal or confidential data out of prompts unless your organisation allows it.

    Keep the prompts that work. A small library of tested prompts – with a note on which model and settings they were used with – saves time and makes results more consistent across a team. The other prompt tools on this site help you format, template, fill and measure them.

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