JSON Validator
Check and validate JSON against the RFC 8259 standard. Detect syntax errors, missing commas, unclosed brackets, and trailing commas instantly.
Step-by-Step Instructions
Paste JSON Code
Paste JSON data into the editor or upload a .json file.
Execute Syntax Validation
Run real-time RFC 8259 schema validation with automated error detection.
Locate Syntax Errors
Inspect highlighted line numbers and character offsets explaining exact syntax issues (trailing commas, unquoted keys).
Auto-Fix Common Errors
Use 1-click Auto-Fix to automatically correct single quotes, unquoted keys, and trailing commas.
Key Features & Capabilities
- Strict RFC 8259 compliant JSON syntax validator with pinpoint line and column error diagnostics
- Automated error fixer resolving single quotes (`'key'`), trailing commas (`,}`), and unquoted property names
- JSON Schema (Draft 7 / 2020-12) validation and data type enforcement
- Tree view explorer with object depth counters and array length indicators
Frequently Asked Questions
What are the most common reasons why JSON validation fails?
1) **Trailing commas** after the last element in an array or object (`{"a": 1,}`); 2) **Single quotes** (`'key'`) instead of double quotes (`"key"`); 3) **Unquoted keys** (`{key: 1}`); 4) **JavaScript comments** (`//` or `/* */`), which are illegal in standard JSON; 5) **Special numbers** (`NaN`, `Infinity`, which are unsupported in JSON).
What is JSON Schema validation?
JSON Schema is a declarative standard for validating the structure, required fields, and data types of JSON documents. It verifies not just syntax, but business rules (e.g., verifying `age` is an integer $\ge 0$ and `email` matches an email format regex).
Can this validator fix broken JSON automatically?
Yes. Our validator includes a smart Auto-Fix engine that automatically converts single quotes to double quotes, strips trailing commas, quotes bare identifier keys, and removes comments.
Is this JSON validator safe for confidential API keys and user data?
Yes. Validation runs 100% locally in your browser's memory using JavaScript web workers. No data is ever transmitted to an external server.
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