Mock JSON

Generate mock JSON from preset shapes (user, post, product, address, payment, comment) or define your own schema. Pick item count (1-1000), nesting depth, and whether arrays embed inline. Output is realistic-shaped JSON suitable for stub APIs, fixture files, and Storybook stories.

Why mock JSON shape matters

Real APIs return objects with specific structure — users is an array, user.id is a string, user.address.country is two letters. A hand-rolled mock that gets the structure wrong wastes more time than not having a mock. Generated mocks based on real shapes save the setup tax.

Preset shapes

• User — id, name, email, avatar, role, createdAt
• Post — id, title, body, author, tags, publishedAt
• Product — id, name, sku, price, currency, stock, category
• Order — id, status, items[], total, customerId, createdAt
• Comment — id, postId, author, body, createdAt
• Address — street, city, state, zip, country, lat, lng
• Payment — amount, currency, method, status, fees
• Event — id, type, source, timestamp, payload

Output options

• Array of items — [{...}, {...}]
• Single item — {...}
• Paginated — { data: [...], page, total, hasMore }
• NDJSON — one object per line for streaming consumers

Common workflows

Stand up a stub API. Generate 50 users as paginated JSON, drop into a users.json file, mock-server points at it. Frontend works against fake data while backend is being built.

Fill a Storybook table. Generate 20 row objects, paste into the story file. The grid renders with realistic content.

Stress-test a list view. Generate 1000 items, set as the data prop. Watch your virtual scroller, sort, and filter handle the load.

Schema-first design. Sketch the shape in this tool, get JSON, share with backend. The schema becomes the contract.

Why generated locally

A JSON mock generator does no harmful work — but it also has no business calling a server. Local generation is faster, available offline, and produces no telemetry. Open the tool, get the JSON, move on.

Last updated: 2025-01-15