Mock JSON Generator

Build realistic mock payloads for tests, demos, and seeded fixtures with a visual structure builder, JSON Schema mode, and local-only processing.

Build realistic JSON payloads locally with seeded reproducibility, schema-driven generation, and reusable templates. No data leaves your browser.
6 nodesPreview 50
Ready to generate mock JSON.
6 nodes1.3 KB template

How to Use

  1. Choose Visual Builder for a no-code workflow or switch to JSON Schema for contract-driven generation.
  2. Load a template, adjust fields, record count, seed, locale, and preview settings.
  3. Generate the output, inspect the preview or raw JSON, then copy or download the result.
  4. Save strong templates locally when you want to reuse the same generator configuration later.

Related Tools

JSON Pretty Print & ViewerJSON Schema ValidatorJSON Grid ViewerJSON Path Finder

Frequently Asked Questions

Can I generate mock JSON without writing code?

Yes. The Visual Builder mode lets you add objects, arrays, and fields interactively, then tune the generation strategy, ranges, and probabilities from the inspector.

Does the tool support JSON Schema generation too?

Yes. Advanced users can switch to JSON Schema mode, validate the schema locally, and generate seeded data from it while still using the same output and audit workflow.

Can I reproduce the same output again later?

Yes. Set a numeric seed and keep the same structure, locale, and options. The generator uses that seed to produce deterministic output that is easy to reuse for tests and fixtures.

Are my templates or generated payloads uploaded anywhere?

No. Generation, template storage, schema validation, and downloads all happen locally in your browser. Nothing is uploaded or stored on a server.