How to use the random data generator
Choose a mode, set the controls it shows, and read the result in Generated output. Password, String, Number, and UUID create one or more standard values. Test Data creates selected synthetic fields and can repeat the same rows when you reuse the Seed, field selection, and Quantity.
- Choose Password, String, Number, UUID, or Test Data.
- Set the controls shown for that mode.
- For a standard mode, adjust Bulk when you need multiple values.
- Read the result in the read-only Generated output area.
- Select Copy or Download for standard output, or Download test data for an export file.
Generate random passwords, strings, numbers, and UUIDs
Password mode combines the checked groups, A-Z Uppercase, a-z Lowercase, 0-9 Digits, and !@#... Symbols. Length accepts 4 to 128 characters. No ambiguous (0, O, I, l, 1) removes those five characters before generation. Clear every group and generation returns an error.
String mode accepts Length from 1 to 256 and one Character set. The choices are Alphanumeric (A-Z a-z 0-9), Lowercase (a-z), Uppercase (A-Z), Digits (0-9), and Hex (0-9 a-f). Number mode returns an integer between Min and Max, inclusive. UUID mode returns RFC 4122 UUID v4 values.
Password, String, Number, and UUID use crypto.getRandomValues(). For Password and String, the Entropy Meter calculates bits from the selected character pool and Length, then labels the result Weak, Fair, Good, or Strong. The number describes the configured pool and length.
Make reproducible test data with a seed
Test Data starts with Email and Username selected. Add Test Card, User-Agent, API Request ID, Reserved Domain, Test URL, IPv4 (doc-safe), IPv6 (doc-safe), MAC (local admin), Timestamp, UUID v4, Coupon Code, Order Number, Invoice Number, Fictional Company, SKU, or Tracking Number (non-real). Set Quantity, enter a Seed, and choose JSON or CSV in Format.
For example, with Email and Username selected, Quantity set to 1, Seed set to 12345, and Format set to JSON, the seeded output is:
[
{
"email": "[email protected]",
"username": "quick_pixel5869"
}
]The same Seed, fields, and Quantity reproduce those rows. Test Data uses reserved domains, documentation-safe IP ranges, locally administered MAC addresses, format-only Test Card values, and tracking values with a TEST-TRACK- prefix. These fields are for test fixtures, not real identities or credentials.
Random data generator limits and output behavior
Bulk controls standard modes and accepts 1 to 1,000 values. Standard values appear one per line. Test Data has its own Quantity control, capped at 1,000, and exports rows as JSON or CSV. Changing a mode or setting updates the output automatically.
Number mode parses Min and Max as base-10 integers. A decimal such as 12.7 is read as 12. An empty value, a non-numeric value, Min greater than Max, or a range with more than 4,294,967,296 values produces an error. If you clear every Test Data field, the output is emptied and the counter shows 0 items.
The page scripts do not call fetch, XMLHttpRequest, or sendBeacon, and they do not submit a form with the generated output. Standard output downloads as random-data.txt. Test Data downloads as test-data.json or test-data.csv.
Where random test data comes up
- A form test can use reserved emails, usernames, URLs, and documentation-safe IP addresses instead of contact details from a real person.
- An API test can select API Request ID, UUID v4, Timestamp, and User-Agent, then export the rows as JSON or CSV.
Use Dataset Generate Tools when you want to browse the wider dataset-generation category; use this page when the needed output is a random value or a selected set of synthetic fields.
Frequently asked questions
How do I generate random passwords, strings, numbers, or UUIDs?
Select Password, String, Number, or UUID, set its controls, and read the automatically updated Generated output. Bulk creates up to 1,000 standard-mode values, one per line.
How do I make reproducible test data?
Open Test Data, select the fields, set Quantity and Format, and enter the same Seed each time. The same seed, field selection, and quantity reproduce the same synthetic rows.
What does the Entropy Meter show?
For Password and String, the Entropy Meter shows a bit calculation based on the selected character pool and Length. It updates when those settings change. Number and UUID do not recalculate it, while Test Data hides the meter.
Why did Number mode return an error?
Number mode errors when Min or Max is invalid, Min is greater than Max, or the integer range is larger than 4,294,967,296 values. Enter base-10 integer values with Min no greater than Max.