Mock Data Generator

How to use Mock Data Generator

1. Edit the Schema: give each field a name and pick a type, such as Full name, Email, UUID v4, Integer (range) or One of a list. Use Add field, the arrows and the remove button to shape it; Reset schema restores the starting fields.
2. Fill in any options a type needs, such as Min and Max, From and To dates, Values (comma separated) or a Pattern.
3. Under Output options, set the number of Rows and choose a Format: JSON, JSON Lines, CSV or SQL (with a SQL dialect and Table name).
4. Keep the Seed to get the same data again, or click New seed for different data.
5. Copy or download the result, or open it in another tool with Send to….

How it works

Every value comes from a seeded random generator (sfc32, seeded by hashing the Seed text), so the same schema, row count and seed always give exactly the same rows. Names, cities and companies are combined from small built-in lists: 82 first names, 75 last names and 48 cities in 31 countries. Within a row, name, email and username are built from the same person, and city and country belong together.

Test-safe values are used where it matters: emails use example.com, example.org, example.net, mail.test or inbox.test, URLs use similar reserved domains, phone numbers use the fictional 555-01xx range, and IPv6 addresses use the documentation prefix 2001:db8::/32. Custom pattern replaces # with a digit, ? with a capital letter and * with either, and \ makes the next character literal. Dates are picked from the whole range in UTC; ISO date-time values look like 2024-05-17T08:21:43Z.

JSON keeps numbers and booleans typed, CSV is RFC 4180 with a header row, and SQL is a CREATE TABLE plus INSERT statements in batches of 500 rows, built by the same generator as the JSON to SQL tool. The schema is checked first: empty or duplicate names, a minimum above the maximum, or dates not written as YYYY-MM-DD are listed, and no data is produced until they are fixed. Everything runs in your browser.

Limits

• At most 10,000 rows; larger numbers are capped.
• Decimal (range) supports 0 to 10 decimal places, and Integer (range) needs a range within JavaScript’s safe integers.
• The name, city and company lists are small and mostly English, so values repeat in large data sets.
• IPv4 addresses are random values from 1.x.x.x to 223.x.x.x, not a reserved test range, so some may belong to real hosts.
• Values come from a reproducible generator, not a secure one, so don’t use the UUIDs or patterns as secrets or real identifiers.
• Fields can’t reference each other beyond the built-in name/email/username and city/country links, and there are no nested objects or arrays.

Privacy

Data is generated entirely in your browser and nothing is uploaded or stored. The Share button copies a link with your schema, row count, seed and output options in its # fragment, which browsers don’t send to servers; whoever opens it gets the same data. Send to… passes the output to another tool through this tab’s session storage, and it is removed as soon as that tool reads it.

Frequently asked questions

Can I get the same data again?

Yes. The output depends only on the schema, the row count and the Seed, so keeping the seed, or sharing the link, reproduces it exactly. Click New seed for a different data set.

Are the emails and phone numbers real?

No. Emails and URLs only use reserved domains such as example.com and .test, and phone numbers use the 555-01xx range kept for fiction, so nothing reaches a real person.

How do I make IDs like ORD-1234-AB?

Choose Custom pattern and type ORD-####-??. Each # becomes a digit and each ? a capital letter; * gives a letter or digit, and \# keeps a literal #.

Which SQL databases are supported?

PostgreSQL, MySQL, SQLite and SQL Server. The output creates the table and inserts the rows in batches of 500, using the Table name you enter (or mock_data).