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JSON Validator

Check whether JSON is syntactically valid and inspect its root structure.

Your data is processed locally in your browser and is never uploaded.Maximum: 4 MB per file. Input is not saved in browser storage or placed in the URL.
Output

How to use this tool

  1. Paste or load JSON, then run validation to receive a diagnostic or structural summary.
  2. Review the live result and use Copy result when you need to share it.

How the transformation works

Native parsing identifies invalid syntax; no schema or business rules are inferred. Processing runs entirely in this browser. The page does not upload, persist, execute or remotely inspect the supplied content.

Processing rules

Native parsing identifies invalid syntax; no schema or business rules are inferred. Processing runs entirely in this browser. The page does not upload, persist, execute or remotely inspect the supplied content.

Step-by-step transformation

  1. Paste or load JSON, then run validation to receive a diagnostic or structural summary.
  2. Native parsing identifies invalid syntax; no schema or business rules are inferred. Processing runs entirely in this browser. The page does not upload, persist, execute or remotely inspect the supplied content.
  3. Check the displayed result, then copy it if needed.

Worked example

A nested object reports its root type, object count, arrays and maximum depth.

Methodology and review

Who this is for

Developers checking whether a payload is syntactically valid JSON.

Inputs and units

  • JSON text or local file

Method

Input is parsed against the JSON grammar and a precise local error is returned when parsing fails.

Worked example

A trailing comma is rejected even though some JavaScript tools accept it.

Assumptions

  • Validation means syntactic JSON validity only.
  • The file is UTF-8 text within the local limit.

Common mistakes

  • Confusing syntax validity with schema validity
  • Using comments in JSON

Limitations

  • The tool does not apply JSON Schema or business rules.
  • A valid document can still be unsuitable for a target API.

How this tool was checked

Tests include valid primitives and structures plus trailing commas, broken strings, and invalid tokens.

Reference sources

Related tools

Calculation review: 21 August 2026. Published by Goldwave Dynamics Limited. This is an internal product review, not an independent certification.

Risk guidance

Frequently asked questions

Does this tool send my inputs anywhere?

No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.

How should I use the result?

Check that the entered units and values match your situation, especially around dates, breaks, and rounding.

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