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JSON Mock rule engine
Developer tools
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All processing for this tool happens in your browser. Your input is not sent to a server.
About this tool
Configure fields with types, numeric ranges, and choices, then use a Seed to generate a repeatable JSON array locally in the browser.
Common uses
- Quickly create test data for API integration, front-end lists, and tables
- Reproduce the same Mock data with a fixed Seed for debugging and screenshots
How to use it
- 1.Add fields and choose string, number, boolean, email, UUID, date, or choice types
- 2.Set the record count and Seed, then fill numeric ranges or choices when needed
- 3.Generate the result, copy the JSON, or download it as a file
Limits and notes
- Strings are readable local placeholders and emails use the reserved example.test domain; results are for development testing, not real identities or contact details.
Frequently asked questions
Does the same Seed produce the same result?
Yes. The output is repeatable when the Seed, fields, and rule order stay the same.
Is my data uploaded?
No. Rules and results stay in the current browser; the tool does not call an API or send data to a server.