Test Data Generator Online - Free Mock & Fake Data Generator
Generate realistic test data in JSON, CSV, XML, and SQL formats with 30+ data types. Fast, secure, and completely free. All processing happens in your browser — no data is sent to any server.
What is a Dataset Duplicator?
The Dataset Duplicator is a free online tool for generating realistic test data from a sample of your own. It uses Faker.js to create believable mock data for testing, development, and demonstrations. Whether you need 10 test users or 10,000 product records, this tool generates realistic data instantly with support for JSON, CSV, TSV, XML, and SQL output formats. Perfect for QA engineers, developers, business analysts, data scientists, and product owners who need quality test data without writing code.
How to Use Dataset Duplicator
Choose a sample dataset template (Users, Products, Orders, Employees, Transactions) or paste your own data in JSON/CSV format
Click 'Parse & Configure Fields' to analyze your data structure automatically
For each field, select the generation mode: Keep Original (preserve values), Random (generate new realistic data), or Sequential (auto-increment)
For Random fields, choose from 30+ data types: names, emails, phones, addresses, UUIDs, dates, companies, credit cards, IBANs, and more
For Sequential fields, set a custom prefix and starting number (e.g., USER-1001, USER-1002...)
Enter the number of records to generate (up to 10,000)
Select your output format: JSON, CSV, TSV, XML, or SQL INSERT statements
Click 'Generate' and download your dataset or copy to clipboard
Key Features
30+ realistic data types powered by Faker.js (names, emails, phones, addresses, companies, products, etc.)
Multiple input formats: JSON, CSV, TSV with automatic parsing
100% client-side processing: Your data never leaves your browser
SQL dialect support: Generate INSERT statements for MySQL, PostgreSQL, SQLite
Export options: Download file or copy to clipboard instantly
Why Use Dataset Duplicator?
Creating test data manually is time-consuming, error-prone, and often unrealistic. The Dataset Duplicator solves this by generating believable mock data in seconds. QA engineers use it for comprehensive testing, developers use it for database seeding, and product owners use it for realistic demos. Unlike other tools, it works entirely in your browser - your sensitive data patterns never leave your device. It's completely free with no signup, no limits, and no restrictions.
Common Use Cases
QA Testing: Generate thousands of realistic user records for comprehensive testing
Database Seeding: Create SQL INSERT statements to populate development databases
API Testing: Generate JSON payloads for REST API testing and load testing
Performance Testing: Create large datasets for stress testing applications
Demo Preparation: Generate realistic data for product demonstrations and sales pitches
User Acceptance Testing (UAT): Create believable test scenarios for stakeholders
Data Migration Testing: Generate sample data matching your target schema
Machine Learning: Create training datasets with realistic patterns
Spreadsheet Templates: Export CSV/TSV for Excel, Google Sheets, or other tools
Documentation Examples: Generate sample data for API documentation
Frequently Asked Questions
Is the test data generator completely free?
Yes, 100% free with no limits, no signup required, and no credit card needed. Generate as much data as you need.
Is my data secure?
Absolutely. All processing happens directly in your browser using JavaScript. Your sample data and generated data never leave your device or get sent to any server.
How many records can I generate at once?
You can generate up to 10,000 records in a single batch. For larger datasets, simply generate multiple batches and combine them.
What data types are available for generation?
Over 30 types including: names, emails, phones, addresses, cities, countries, companies, job titles, products, prices, UUIDs, dates, URLs, IPs, usernames, passwords, credit cards, IBANs, SSNs, and more.
Can I generate SQL INSERT statements?
Yes! Select SQL as your output format and get ready-to-use INSERT statements compatible with MySQL, PostgreSQL, and SQLite.
Can I input CSV and output JSON?
Yes! The tool supports cross-format conversion. Input in JSON, CSV, or TSV and output in JSON, CSV, TSV, XML, or SQL.
Does it work for non-English data?
Yes, Faker.js supports multiple locales. The generated names, addresses, and other data can reflect different countries and languages.
Can I use this for API load testing?
Absolutely. Generate thousands of JSON records and use them with tools like Postman, JMeter, or k6 for API performance testing.
How does sequential generation work?
Sequential mode auto-increments values. Set a prefix like 'USER-' and start number 1001, and you'll get USER-1001, USER-1002, USER-1003, etc.
What's the difference between Keep, Random, and Sequential?
Keep preserves your original values, Random generates new realistic data for each record, and Sequential creates incrementing values with optional prefixes.