Sample data tools

Sample JSON Generator

Generate valid JSON test records with no uploads.

Sample JSON Generator: Generate a small, valid JSON array for parser tests, mock responses and list views. Sample JSON Generator writes flat synthetic records with id, label, value and active fields. It supplies a fixed starting shape for fixtures; it does not infer your API schema or reproduce production data distributions. Runs 100% locally in your browser with zero server file uploads.

Category: Developer tools
Runs: In your browser
Cost: Free · no sign-up
Availability: Ready to use

Sample JSON workbenchLocal processing

Runs entirely in your browser

Fictional result

Waiting

Your test-only result will appear here.

Fictional test fixtures only. Do not use these generated identities, addresses, or IDs as real records.

Array-size rule and example object

For requested count n, array length = n. At zero-based index i, value = i + 1 and ID = JSON-TEST- followed by that ordinal padded to four digits. With Rows = 1 and the first label drawn, the single object is {"id":"JSON-TEST-0001","label":"fixture-alpha","value":1,"active":true} inside a formatted array. Here n = 1, i = 0 and 0 + 1 = 1. For count 3, there are three objects with values 1, 2 and 3; whitespace in the formatting does not affect that array length.

Types and safe additions to mocks

RFC 8259 (https://www.rfc-editor.org/rfc/rfc8259) defines JSON syntax; valid syntax alone cannot confirm your business schema. The built-in numeric values stay between 1 and 100, while IDs are strings, avoiding large-number precision problems. If you add example email fields, RFC 2606 (https://www.rfc-editor.org/rfc/rfc2606) reserves example.com. For an added IPv4 documentation field, RFC 5737 (https://www.rfc-editor.org/rfc/rfc5737) provides the TEST-NET blocks; 192.0.2.10 is one such illustrative value, not a live host. No email or IP field is generated automatically, and external calls should be mocked in tests. JSON to JSON Schema can derive a starting schema from a fixture before you refine its constraints.

How to use it

Choose a whole row count from 1 to 100.
Generate a synthetic batch in your browser.
Copy or download the fixture and save it for repeatable tests.

Privacy & limitations

Generation stays on this device. The records are fictional test fixtures; review and isolate the application that consumes them.

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Frequently asked questions

Can I choose my own fields, nesting or schema?

The generator has a row-count control only. All objects have the same four fields, value rises with position and active is always true. Download the array and edit it to add nested objects, missing properties, nulls and false flags, then validate those changes against your intended schema.

Is the output JSON Lines or an API response envelope?

It is one top-level array formatted over several lines, not one complete record per line. An API requiring a data property, total count or pagination metadata needs a wrapper you add yourself. A JSON Lines reader needs the records serialized separately without the enclosing array.

Will a second generation reproduce my first fixture?

Labels are selected afresh from fixture-alpha, fixture-beta and fixture-gamma. IDs and values restart at 1, but labels may differ. There is no seed control in the widget. Save the result in your test fixtures when snapshot or regression tests require a stable expected payload.

Free tool · runs in your browser · no account required