JSON Syntax Validator
About JSON Validator
The JSON Validator & Syntax Linter parses JSON text and highlights exact syntax errors, missing commas, unescaped quotes, trailing commas, and unclosed brackets with line and column error indicators.
How to Use JSON Validator
Step 1
Paste your JSON code into the linter.
Step 2
Inspect the live Validation Status badge (Valid / Invalid).
Step 3
Review highlighted error markers and suggested fixes.
Step 4
Click "Auto-Fix & Format" to repair syntax errors.
Practical Use Cases for JSON Validator
API Error Diagnosis & Debugging
Diagnose JSON parse errors (`SyntaxError: Unexpected token in JSON at position X`) from broken API responses and webhook logs.
Configuration File Verification
Validate package.json, tsconfig.json, and appsettings.json files before deploying code to production servers.
Input & Output Examples
Catching Trailing Comma in JSON Object
{"name": "Elena", "role": "admin", }Syntax Error on Line 1, Column 35: Trailing comma is not permitted in RFC 8259 standard JSON
Key Features & Performance
- ✓Validates strict RFC 8259 and ECMA-404 JSON syntax specifications.
- ✓Pinpoints exact Line and Column number of syntax mistakes.
- ✓Auto-fixes common errors: trailing commas, single quotes to double quotes, unquoted keys.
- ✓100% Client-Side validation.
- ✓1-Click Copy validated and cleaned JSON.
Key Terminology & Definitions
RFC 8259 Standard
The official Internet Engineering Task Force (IETF) specification defining strict JSON syntax rules.
Trailing Comma
A comma placed after the last item in an array or object, which is illegal in strict JSON specifications.