JSON Validator

A precise JSON validator built on the nlohmann library, designed for developers who need fast, accurate syntax and structure validation without leaving their environment.

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1,704+

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 JSON Validator 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

Performs syntax validation of JSON strings by parsing input with the nlohmann/json library. On success, the input is parsed to a DOM-like structure; on failure, an error with position is produced.
If a JSON Schema is provided, the tool validates the parsed data against the schema, reporting all violations; when absent, only syntax and basic structure are checked.
Target users include C++ developers, testers, and automation engineers who need deterministic validation as part of code, tests, or CI pipelines.
Unique value lies in precise error localization, robust handling of edge cases (empty input, UTF-8 issues), and the ability to operate in isolation or as part of larger tooling.
Core features include quick syntax checks, optional schema validation, streaming for large payloads, and clear structured error reports.

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How to Use

Provide inputs: paste the JSON text into json_text.
Optional: supply a json_schema to enable structural validation.
Run validation: trigger parsing and schema checks.
Review outputs: examine is_valid and the errors array with line and column.
Iterate: fix issues in the JSON and re-run validation.

Frequently Asked Questions

Find Quick Answers

What inputs are required?

json_text is required; json_schema is optional. The tool returns a boolean is_valid and a detailed errors array that lists line and column where parsing or schema violations occur, enabling targeted fixes.

Does it support JSON Schema validation?

Yes, optional schema validation can be enabled by providing a JSON Schema. Without a schema, the tool validates only syntax and basic structural conformance; with a schema it reports violations against defined rules.

How large of a payload can it handle?

The validator is designed to handle typical JSON payloads efficiently; for very large inputs memory usage depends on the parsing method and available system resources. Streaming options help reduce peak memory for large streams.

How can I integrate it into CI?

The tool exposes a programmatic API and can be invoked via a CLI in automated pipelines. It returns structured results and exit codes, allowing easy integration into build steps and test suites.

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