Mock JSON Data Generator

Build a custom schema and generate up to 1,000 fake JSON records for testing, demos, prototypes and seeding databases. Everything runs in your browser — your schema is never sent anywhere and all the data is fictional and synthetic.

Field name Type

How to use the mock JSON generator

  1. Define your schema: give each field a name and pick a type. Use + Add field for more, or × to remove one.
  2. Set how many records you want (up to 1,000).
  3. Click Generate, then Copy the JSON or Download .json.

The output is a JSON array of objects, pretty-printed with a 2-space indent. Every value is fake and synthetic — fictional names, emails, addresses and companies safe for tests, demos, fixtures and seed data. Nothing you enter or generate leaves your browser.

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Frequently asked questions

Is the generated data real?

No. Every value is fake and synthetic, assembled from small built-in word and name lists and random numbers. Names, emails, addresses and companies are fictional and are meant only for testing, demos, seeding databases and prototyping — they do not refer to real people or organisations.

Is my data sent anywhere?

No. The generator runs entirely in your browser — your schema and the output are never uploaded to a server and nothing is stored. You can use it offline once the page has loaded.

How many records can I generate?

You can generate up to 1,000 records at a time. The output is a standard JSON array, pretty-printed with a 2-space indent, which you can copy or download as a .json file.

What field types are supported?

You can mix identifiers (id, uuid), people (full / first / last name, email, username, phone), places (country, city, street address), work (company, job title), plus boolean, integer, decimal, date, datetime, color hex, URL, IPv4, a lorem paragraph and an avatar URL.

Are the UUIDs valid v4?

Yes. UUIDs are generated as RFC 4122 version 4 values using crypto.getRandomValues, so they are cryptographically random and correctly versioned.

Can I choose my own field names?

Yes. Each field has a name you type and a type you pick from the list. Add as many fields as you like, remove any with the × button, then click Generate to build the JSON.