JSON Mock Data Generator

Build your schema and generate realistic fake data instantly. 30+ types, presets, Web Worker-powered — everything stays on your device.

Loading Tool...

💡Help shape DevUtils.lol

No black-box support tickets. DevUtils.lol is built for you. Report bugs directly to our public repo, or come hang out with other devs in the community.

Frequently Asked Questions

30+ types across 9 categories: Person, Internet, Location, Phone, Company, Finance, Data, Text, and Commerce. From UUIDs to credit cards to avatars.

Up to 100,000 rows. A Web Worker generates data off the main thread so the UI never freezes, even for massive datasets.

Yes. One-click presets for User, Product, Address, and Company schemas instantly configure realistic field combinations.

Yes. Add fields with custom names and choose from any of the 30+ data types. The schema editor lets you build exactly the structure your API needs.

All generation runs locally in your browser via a Web Worker. No data is sent to any server.

JSON Mock Data Generator — 30+ Types, Local - Privacy-First, Offline Developer Tool

Global Architecture: This tool runs entirely in your browser using WebAssembly. Unlike server-side alternatives, your data (JWTs, Logs, SQL) never leaves this device. It works offline and handles massive files (1GB+) bounded only by your RAM.