JSONata tester

A focused tool to test JSONata expressions against JSON data, helping developers validate mappings and transformations quickly.

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Request Feature / Support

1,264+

Total Calculations Run

< 15ms

Browser Execution Speed

100%

Client-Side Privacy

4.9 / 5.0

User Satisfaction

Worked Example & Common Values

Below is a sample worked calculation demonstrating how JSONata tester processes input data instantly inside your browser.

Sample Input Minified string: {"id":1,"status":"active","roles":["admin"]}

Computed Result

{
  "id": 1,
  "status": "active",
  "roles": [
    "admin"
  ]
}

Execution Mode Client-Side In-Browser JS

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About This Tool

The JSONata tester provides an isolated, offline-capable environment to evaluate JSONata expressions against sample or real JSON data. It conceptualizes mappings as a transformation workflow: input JSON is parsed, the expression is applied, and a transformed output is produced. This allows developers, data engineers, and integration specialists to verify correctness before deploying data pipelines. Core value comes from immediate feedback on path navigation, function calls, and array mappings, plus detailed error diagnostics when expressions fail. Users benefit from deterministic results, repeatable test scenarios, and the ability to unit-test complex transformations without relying on external services. High-value differentiators include structured error codes, verbose evaluation traces, and support for multiple test datasets in a single session. The tool supports common JSONata constructs such as object construction, arrays, conditionals, and user-defined functions, enabling rapid iteration over transformation logic. Use cases include API data shaping, ETL mapping validation, and client-side data shaping for front-end apps. The tester emphasizes correctness, reproducibility, and lightweight testing latency, making it suitable for developers integrating JSONata into data workflows and automation scripts.

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How to Use

Provide inputs: supply a JSON document and a JSONata expression to test.
Run evaluation: execute the expression against the input data to compute the transformed output.
Review outputs: inspect the transformed JSON and any diagnostic messages or timing metrics.
Iterate: adjust the expression or dataset and retest to converge on the desired mapping.
Export: save the result set or import into downstream pipelines as needed.

Frequently Asked Questions

Find Quick Answers

How does the tester handle missing paths in the input JSON?

Missing paths evaluate to null by default unless a fallback is provided in the expression. The tool surfaces precise path traces in errors to aid debugging and shows where each value was resolved or omitted.

Can I test multiple expressions against the same input data?

Yes. You can add multiple expression-test pairs within a session and run them in sequence. Each result is displayed with independent outputs and diagnostics to compare behavior side-by-side.

Does the tester support exporting results for pipelines?

Yes. Results can be exported as JSON, including transformed output, source data, and diagnostic metadata, enabling integration with automated workflows and validation reports.

Are functions and operators in JSONata fully supported?

The tester implements the standard JSONata function set and operators. Complex functions are executed with deterministic semantics, and errors include location and cause to aid correction.

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