JSON Mock Generator
Build a schema visually and generate realistic mock JSON data with names, emails, dates, IDs, and more.
About this tool
Mock data is synthetic data that simulates the structure and values of real data for use in development, testing, and documentation. Well-crafted mock data resembles real data closely enough to reveal design and usability issues during prototyping. Generic placeholder data (id: 1, name: 'Test User', email: '[email protected]') can mask problems that only appear with realistic data — such as what happens when a name is very long, when a date is in the past versus the future, or when a numerical value is near a boundary.
Schema-driven mock generation produces data that matches your API's actual data model, making it useful for building realistic frontend prototypes before the API is ready, populating development databases with enough varied data to test pagination and search behavior, writing automated tests with known inputs, creating demo environments for client presentations, and documenting API responses with realistic examples.
Quality mock data uses realistic distributions: names drawn from diverse name pools, email addresses with plausible domain names, dates within reasonable ranges for the context, IDs that look like real identifiers (UUIDs for modern APIs, sequential integers for simpler systems). When building integrations, testing with a mock data set that covers edge cases — maximum string lengths, special characters, null values, and boundary numbers — is essential for discovering edge case bugs before they appear in production.