Online JSON Validator & Linter

Validate JSON syntax against RFC 8259 standards. Locate errors like trailing commas or missing quotes instantly.

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Input

JSON

Output

Parsing Panic: Why Your JSON is Breaking

JSON appears deceptively simple, but it is brutally strict compared to the JavaScript objects it mimics. A single misplaced comma, a forgotten closing brace, or using single quotes instead of double quotes can cause your entire application to crash with a parser error. Our JSON Validator serves as a robust linter for your data. It adheres strictly to RFC 8259 standards, scanning your payload not just for basic syntax errors, but for subtle issues like control characters or encoding mismatches that traditional text editors might hide.

The "Trailing Comma" and Quote Consistency

The most frequent culprit in JSON validation failures is the "Trailing Comma." In modern JS, Python, or Go, leaving a comma after the last item in an array `[1, 2,]` is acceptable or even encouraged. In JSON, it is a syntax error. Furthermore, keys must always be wrapped in double quotes (`"key": "value"`). Our tool highlights these specific violations instantly. It acts as a sanitizer before you commit code or send a request to an API endpoint, ensuring your data is "machine-readable" in the strictest sense.

Debugging APIs and Config Files

Whether you are configuring a `.json` file for a build tool or debugging a REST API response, structure is everything. Validating manually is prone to human error, especially with deeply nested objects. This tool parses the logic tree of your JSON. If you paste a Minified JSON string, it will implicitly format and check it, giving you a clear report on structural integrity. It prevents the scenario where a deployment fails because of a missing comma in a 500-line configuration file.

FAQ
This is the generic error message from the JSON parser. It usually means you have a trailing comma, a missing quote, or you are using single quotes. Our tool pinpoints the exact line number to make this message actionable.
Standard JSON does not support comments (`//` or `/* */`). Douglas Crockford removed them to prevent people from using JSON as a configuration language with directives. Using comments will trigger a validation error.
Yes. According to the latest standards, a standalone primitive value like `123`, `"hello"`, `true`, or `null` is considered a valid JSON text, although most practical uses involve arrays or objects.
Yes. We employ a strict "Client-Side Only" policy. The validation logic runs within your browser using JavaScript. No data is sent to our servers, ensuring your API keys and PII remain private.
This tool validates "Syntax" (is it valid JSON?), not "Schema" (does it have the required fields?). For schema validation (e.g., checking if "email" is actually an email), you would need a JSON Schema Validator.