Mock API Data Tool

How to use: step by step

1. 1
   Define your schema
   Edit the JSON schema to describe the shape of your API response. Use built-in types like uuid, fullName, email, number:min:max, and more.
2. 2
   Set the record count
   Choose how many records to generate: from a single object to hundreds of rows for pagination testing.
3. 3
   Generate data
   Click Generate to produce a JSON array populated with realistic fake values matching your schema.
4. 4
   Copy the JSON
   Click Copy to grab the output and paste it into your frontend code, Postman mock, or API testing tool.
5. 5
   Iterate quickly
   Adjust the schema and regenerate instantly to try different data shapes as your API design evolves.

Frequently Asked Questions

What is a mock API?

A mock API is a simulated API endpoint that returns fake but realistic data. It allows frontend developers and testers to work independently of the real backend, speeding up development and enabling testing scenarios that are hard to trigger with live data.

What field types are supported in the schema?

The generator supports common types including uuid, fullName, firstName, lastName, email, phone, address, number (with optional min/max), boolean, date, and more. Check the schema editor for the full list of supported type tokens.

Can I generate nested objects?

Nested JSON objects can be defined by using object values in the schema. For example, set an 'address' field to contain street, city, and country sub-fields.

Is the generated data realistic?

Yes. Names, email addresses, and other personal data fields are generated using realistic patterns: not random character strings. This makes the output useful for UI testing where the data needs to look plausible.

How do I use the generated data with a real API testing tool?

Copy the JSON output and paste it into Postman as a mock response body, use it as a fixture file in your test suite, or serve it locally with a tool like json-server to create a fully functional mock endpoint.

Is generated data GDPR-compliant for use in tests?

Yes. All data is synthetic: it does not contain real personal information. Using synthetic test data rather than production data is a GDPR best practice.

Can I generate CSV instead of JSON?

The current tool outputs JSON, which maps naturally to REST API responses. To convert to CSV, paste the JSON into a JSON-to-CSV converter tool.

How many records can I generate at once?

You can generate large batches of records in a single click. For very large datasets, consider copying the output to a file and serving it with a local mock server.

Can I use number:min:max to control ranges?

Yes. Use the token number:18:65 to generate integers between 18 and 65 inclusive, which is ideal for fields like age, score, or quantity.

Does the data include null values?

By default, all fields are populated. You can optionally add nullable field definitions to the schema to test how your UI handles missing data.