Fake JSON Data Generator mock
Describe fields and types, then generate as many mock rows as you need in JSON, NDJSON, or CSV.
What this tool does
Building a screen or wiring up an API usually happens before real data exists. A list needs a dozen entries before scrolling and pagination can be checked, and names of varying length are what expose the point where a layout breaks. Hand-written samples tend to be too uniform to reveal any of that.
Write one field per line with its type and this tool generates matching data. Supported types include id, uuid, name, email, phone, city, company, url, ipv4, boolean, int, price, date, datetime, timestamp, status, and sentence; anything unrecognised falls back to a sentence.
Three output formats are available. A JSON array mimics an API response, NDJSON suits log pipelines and bulk loading tests, and CSV moves straight into a spreadsheet or a database import. Everything is generated in the browser and nothing is transmitted.
When to use it
Use it to fill a list screen while building the frontend, to add response examples to documentation, to create test records for a database, to exercise pagination and sorting, or to prepare input for a load test.
Input and output examples
id: id
name: name
email: email
active: boolean
[{"id":1,"name":"alice kim","email":"alice381@example.com","active":true}, ...]
One field per line produces exactly that structure.
CSV output selected
id,name,email,active
1,alice kim,alice381@example.com,true
Ready for a spreadsheet or a database import.
Notes and limitations
Values are random combinations and reflect neither the distribution nor the constraints of real data. Generated email addresses look plausible but do not exist, so never use them for delivery tests, and the same applies to phone numbers. No logical relationships are created either: an order date may precede a signup date, so adjust after generating when ordering matters. Do not leave data that imitates personal information sitting in a production database.
Frequently asked questions
Can I send mail to the generated addresses?
No. They use example domains and do not exist. Use an address you control for delivery testing.
What happens with an unknown type?
It falls back to the sentence type and a notice is shown. The question mark button lists every available type.
Can fields relate to each other?
No. Each field is generated independently, so constraints such as date ordering must be applied afterwards.