Form to JSON Schema

Reverse engineer HTML forms into JSON schema definitions. Paste any HTML form and extract field names, types, validation rules, and options into a reusable JSON format.
HTML Form
JSON Schema
Extracted JSON schema will appear here...

What Gets Extracted

  • • Field names, types, and labels from inputs
  • • Validation attributes (required, min, max, pattern)
  • • Select options with values and labels
  • • Placeholder text and help content

How to Extract JSON Schema from an HTML Form

  1. 1

    Paste Your HTML Form

    Copy the HTML source of any form element and paste it into the input panel. The tool accepts complete form tags, individual input elements, or entire page snippets containing forms.
  2. 2

    Click Extract Schema

    Press the Extract Schema button to parse the HTML. The tool analyzes every input, select, textarea, and label element, detecting validation attributes such as required, minlength, maxlength, and pattern.
  3. 3

    Review the JSON Output

    Inspect the generated JSON schema in the output panel. Each field includes its name, type, label, placeholder, and any validation rules found in the original HTML markup.
  4. 4

    Copy or Download the Schema

    Use the copy button to place the schema on your clipboard, or download it as a JSON file. You can then feed it directly into a form generator to rebuild the form in any framework.

Common Use Cases

1

Framework Migration

Moving a legacy HTML form to React, Vue, or Angular? Extract the schema first, then use a form generator to produce framework-specific code without manually re-typing every field and validation rule.
2

Design System Audits

Catalog all form fields across a website by extracting their schemas. Compare field names, types, and validation patterns to find inconsistencies and enforce standards across your design system.
3

API Contract Generation

Turn a front-end form into a JSON schema that doubles as an API request contract. Share the schema with backend developers so the request body matches exactly what the form collects.
4

Automated Testing Setup

Generate test fixtures from real forms. The extracted schema gives you every field name and validation constraint you need to write comprehensive form-level tests quickly.

Why Use Form to JSON Schema?

Need to recreate an existing form in a different framework? This tool extracts the structure of any HTML form into a portable JSON schema that you can use with our JSON-to-form generators or your own code generation tools.

Form to JSON Schema is a free online tool that reverse engineers any HTML form into a structured JSON schema. Whether you are migrating a legacy application, auditing form fields across a large website, or generating API contracts from front-end code, this tool saves hours of manual work by automatically detecting input types, labels, placeholder text, and validation attributes such as required, minlength, maxlength, and pattern.

The extracted schema is fully compatible with other FindUtils form generators. Paste the output directly into the JSON to HTML Form generator, the JSON to Tailwind Form generator, the JSON to Bootstrap Form generator, or the JSON to React Form generator to recreate the form in any framework within seconds. You can also feed the schema into the JSON Schema Form Builder for a visual drag-and-drop editing experience.

All processing happens entirely in your browser. No HTML is uploaded to any server, making this tool safe for proprietary codebases and sensitive projects. Combined with the JSON Schema Generator and the JSON Schema Validator, FindUtils provides a complete workflow for working with JSON schemas from start to finish.

How It Compares

Most JSON schema tools start from raw JSON data, but Form to JSON Schema works in the opposite direction: it starts from an HTML form and produces a schema that describes the form's structure. This makes it uniquely useful when you need to document or migrate existing user interfaces rather than data models. Unlike manual inspection with browser DevTools, this tool extracts every field in one step and outputs a clean, downloadable JSON file ready for code generation.

Compared to paid form-builder platforms that lock you into a subscription, Form to JSON Schema is completely free with no signup and no usage limits. Because extraction runs client-side, your HTML never leaves your machine, an important advantage when working with internal or proprietary forms that should not be sent to third-party servers.

Tips for Better Results

1
Include the complete form tag with all child elements for the most accurate extraction.
2
Make sure label elements use the for attribute so the tool can associate labels with their inputs.
3
Wrap radio and checkbox groups inside a fieldset so the tool can detect related options.
4
If your form uses custom web components, ensure the underlying native input elements are present in the HTML you paste.
5
Use the extracted schema with the JSON Schema Form Builder to visually edit fields before generating code.

Frequently Asked Questions

1

What HTML elements are detected?

The tool extracts input, select, and textarea elements. It also detects associated labels and validation attributes like required, min, max, and pattern.
2

Does it preserve all attributes?

The tool extracts the most commonly used form attributes including name, type, placeholder, required, and validation rules. Custom data attributes are not included.
3

Can I use the output with your generators?

Yes! The JSON schema output is designed to be compatible with our JSON to HTML Form, Tailwind Form, Bootstrap Form, and React Form generators.
4

How are radio buttons handled?

Radio buttons with the same name are grouped together with their individual options and labels extracted into an options array.
5

What if the HTML is malformed?

The tool uses browser HTML parsing which is forgiving of minor errors. However, severely malformed HTML may not extract correctly.

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