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Mock JSON Data Generator

Paste a JSON Schema or sample JSON and generate realistic fake test data — instantly.

Schema / Sample JSON

Mock Data

Generate Realistic Mock JSON Data

Once you have a shape for your data — a JSON Schema from the Schema Generator, or just a sample response — the next thing you usually need is a batch of realistic-looking fake records to populate a UI, seed a database, or write tests against. This tool generates that data for you: paste a JSON Schema or a sample JSON object, choose how many rows you want, and get back properly shaped fake data with names, emails, IDs, and other fields that actually look real — not just repeated placeholder text.

How It Works

  • Paste a JSON Schema or a sample JSON payload into the left editor, or click Sample to try an example schema.
  • Set the row count (1–500) and click Generate — each row is generated fresh from the same shape.
  • Field names drive realism: a field called email gets a real-looking email, firstName gets a first name, createdAt gets a timestamp, and so on — not just a random string.
  • Switch to CSV if you need the output in a spreadsheet-friendly format instead of JSON.
  • Copy or download the result directly into your project or test fixtures.

Schema Input or Sample Input — Both Work

You can paste either a full JSON Schema (with type, properties, and format keywords — exactly what the JSON Schema Generator produces) or just a plain sample JSON object or array. When you paste a schema, declared format values like email, uuid, and date-time are honored directly. When you paste a sample, the tool infers the shape and uses each field's name and original type to pick a realistic generator — so a numeric id stays a number instead of turning into something else.

Privacy

All data generation happens entirely in your browser using JavaScript. Your schema or sample data — and the fake data generated from it — never leaves your device.

Mock Data Generator — Options Explained

Here's what drives the realism of the generated fields, and what each option on this page controls.

Field-Name Detection

Field names like email, phone, city, company, or price are matched against common naming patterns to pick a realistic generator, instead of producing generic placeholder text for every field.

Type-Aware Generation

The original value's type is respected — a numeric id stays a number, a boolean stays true/false, and nested objects and arrays are generated recursively, matching the structure you provided.

JSON Schema Formats

When you paste a JSON Schema, the format keyword (email, uuid, date, date-time, uri) is honored directly, so schemas from the Schema Generator convert cleanly into mock data.

JSON or CSV Output

Generate a JSON array for use directly in code or a test fixture, or switch to CSV for pasting into a spreadsheet or bulk-importing into a database tool. Nested objects are flattened into dot-notation columns in CSV mode.

Who Uses This Tool?

Frontend Developers

Populate a UI with realistic-looking data before the real API is ready, so tables, cards, and lists don't look empty or fake during development.

QA & Test Engineers

Generate a batch of test fixtures matching a schema, instead of hand-writing dozens of similar-looking JSON objects.

Backend Developers

Seed a development database with realistic sample rows, in JSON or CSV, matching the exact shape of a schema you're building against.

Product & Design Teams

Get believable sample content for mockups and prototypes instead of "Lorem ipsum" and "John Doe" repeated in every row.

Frequently Asked Questions

Does this use the Faker.js library?

No — this tool uses its own lightweight, hand-built data generator (name lists, email patterns, address data, and so on) rather than bundling the full Faker.js library, so the page stays small and fast while still producing realistic-looking fake data.

Can I use a JSON Schema from the Schema Generator?

Yes — paste the output of the JSON Schema Generator directly into this tool. Its type and format keywords are used to pick the right generator for each field automatically.

What if I paste a sample JSON object instead of a schema?

That works too. The tool infers each field's type from your sample value and uses the field name to pick a realistic generator, so you don't need a formal schema to get useful mock data.

How many rows can I generate at once?

Up to 500 rows per batch. For larger datasets, generate in multiple batches and combine the output.

Is my schema or sample data uploaded anywhere?

No. All generation happens locally in your browser with JavaScript. Nothing is sent to a server.

Built by Deepak Kumar — a developer who wanted a JSON tool that respects your privacy. All processing happens in your browser. Your data never leaves your device.