Mock JSON Generator

What it does

The Mock JSON Generator turns a JSON template into realistic, reproducible fixtures. Write your payload’s shape once, drop in typed placeholders — {{id}}, {{number}}, {{boolean}}, {{string}}, {{date}}, {{email}}, {{url}}, {{enum:admin|editor|viewer}} — and generate up to 1,000 records that match it. Nested objects and arrays work naturally because the template is JSON.

Common use cases

• Frontend fixtures — API-shaped data before the API exists; point your components at the generated payloads.
• Integration tests — seeded fixtures that never drift between runs or machines.
• API prototyping — realistic response bodies for mock servers and contract discussions.
• Documentation examples — consistent, clearly synthetic payloads for API docs.

Settings

• JSON template — your structure with placeholders; anything not a placeholder passes through literally.
• Records — 1 to 1,000 objects generated from the template.
• Output — pretty-printed or minified.
• Seed — the same seed and template regenerate identical records — the seed is part of your fixture definition.

Privacy note

Everything is generated locally in your browser and never uploaded. Values are synthetic; emails use the reserved example.test domain, so nothing generated can reach a real inbox.

FAQ

How do enums work? {{enum:a|b|c}} picks one of the listed values per record — ideal for statuses, roles, and plan tiers.

Can I generate arrays of nested objects? Yes — put the array with an object template inside your JSON; each generated record fills the nested placeholders independently.

How is this different from the Random API Mock tool? This one is template-first: you control the exact shape. Random API Mock generates common response patterns for you. Start there for speed, here for fidelity to your schema.