JSON Generator
Generate random JSON test data with visual configuration. Create mock data for API testing with names, phones, dates, arrays, and more.
No fields configured yet.
Click "Add Field" to start building your JSON structure.
Quick Templates
About JSON Generator
Our free online JSON Generator is a powerful tool for creating realistic mock data for API testing, development, and prototyping. Instead of manually writing JSON objects, you can visually configure the structure and data types, then instantly generate random test data that matches your specification.
The generator supports a wide variety of data types including strings, numbers, booleans, dates, emails, phone numbers, URLs, IP addresses, colors, UUIDs, and arrays. Each field can be customized with specific patterns, ranges, and constraints. You can create deeply nested object structures and arrays of varying lengths to match your API response schemas.
Quick templates are available for common data structures like user profiles, products, blog posts, companies, addresses, orders, and employees. These templates provide a starting point that you can customize further. The generated data uses realistic patterns: names from common name lists, phone numbers with proper formatting, valid email patterns, and properly formatted dates.
All generation happens directly in your browser, so you can create unlimited mock data without any server communication. This ensures complete privacy and allows you to use the tool even offline after the initial page load.
Related JSON Tools
Features
Visual Configuration
Build JSON structure visually with drag-and-drop field configuration. No coding required.
Random Data Types
Generate names, emails, phones, dates, numbers, booleans, colors, UUIDs, and more.
Nested Structures
Create deeply nested objects and arrays with custom field configurations at each level.
Quick Templates
Load pre-built templates for users, products, blog posts, companies, orders, and more.
Batch Generation
Generate 1 to 100 records at once. Perfect for testing pagination and list endpoints.
Copy & Download
One-click copy to clipboard or download as a .json file for use in your projects.
Multiple Formats
Output as array of objects or single object. Choose indentation style and compact mode.
Statistics
View field count, record count, output size, and character count for quick overview.
Privacy First
All generation happens in your browser. No data is sent to any server.
How to Use
Load a Template or Add Fields
Click "Load Template" to use a pre-built schema, or click "Add Field" to build your own structure from scratch.
Configure Fields
For each field, set the key name, data type, and any specific options like min/max values, date range, or array length.
Set Options
Choose the number of records, output format (array or single object), and indentation style.
Generate
Click "Generate" to create random data. Use "Regenerate" to get new random values with the same structure.
Frequently Asked Questions
What data types are supported?
The generator supports: String (custom or random text), Number (with min/max range), Boolean, Date (with configurable range), Email, Phone Number, URL, IP Address, Color (hex), UUID, Name (first/last/full), Address, City, Country, Company, Job Title, Paragraph (lorem ipsum), and Array (with configurable length and item type).
How do I create nested objects?
Click "Add Nested Object" to create a sub-object. You can add fields inside the nested object just like at the top level. You can nest objects to any depth, which is useful for matching complex API response structures.
How do I generate arrays?
Click "Add Array" to create an array field. Configure the minimum and maximum array length, and choose what type of items the array should contain (strings, numbers, objects, etc.). The generator will create arrays with a random length within the specified range.
Can I generate data for API testing?
Yes! This tool is designed specifically for API testing and development. Use the quick templates or build custom schemas that match your API response format. Generate multiple records to test list endpoints, pagination, and bulk operations. The generated data uses realistic patterns that closely resemble production data.
Is the generated data realistic?
The generator uses curated lists and patterns to create realistic-looking data: names from common first and last name lists, properly formatted phone numbers and email addresses, realistic dates, valid-looking URLs and IP addresses, and lorem ipsum paragraphs for text content. While the data is random and not real, it closely resembles real-world data patterns.
Can I save my configuration?
While the tool doesn't have a built-in save feature, you can export the generated JSON and use the structure as a reference. You can also bookmark this page with your configured fields by copying the field configuration to a text file for reuse.
Is this JSON Generator free?
Yes, it is completely free to use with no registration, sign-up, or limits. You can generate unlimited mock data for personal, educational, or commercial projects without any restrictions.
Does it work offline?
Yes, once the page is loaded, all data generation happens entirely in your browser using JavaScript. No server communication is needed, so you can use it even without an internet connection after the initial page load.
Is my data secure?
Absolutely. All data generation happens directly in your browser using JavaScript. No data is sent to any server, stored, or logged. This ensures complete privacy for your development and testing workflows.