OpsKitJSON Linter - Online JSON Validator & Syntax Checker
About This Linter
This linter validates JSON syntax and structure using the native browser JSON.parse.
It attempts to surface multiple syntax errors by re-running the parser after masking earlier issues.
All processing happens entirely in your browser - no data is sent to any server.
What is a JSON Linter?
A JSON linter is a tool that checks your JSON data for syntax errors, structural problems, and common formatting issues before that JSON is consumed by applications or APIs. A single misplaced comma, missing quote, or extra brace can break an entire integration.
Why Use This JSON Linter?
| Feature | Description |
|---|---|
| 100% Client-Side | Your JSON never leaves the browser |
| Fast Feedback | Errors highlighted with line-level context |
| Formatted Preview | See pretty-printed version of your JSON |
| Multiple Errors | Surfaces several issues in one pass |
| Safe for Sensitive Data | No backend storage or logging |
Common JSON Syntax Errors
Missing or Extra Commas
The most frequent JSON error is incorrect comma placement:
// Wrong - trailing comma
{
"name": "app",
"version": "1.0", // <-- trailing comma not allowed
}
// Wrong - missing comma
{
"name": "app"
"version": "1.0" // <-- missing comma
}
// Correct
{
"name": "app",
"version": "1.0"
}Unquoted Keys or Single Quotes
JSON requires double quotes for all strings:
// Wrong - unquoted key
{
name: "app"
}
// Wrong - single quotes
{
'name': 'app'
}
// Correct
{
"name": "app"
}Incorrect Data Types
// Wrong - undefined is not valid JSON
{
"value": undefined
}
// Wrong - NaN is not valid JSON
{
"value": NaN
}
// Correct - use null for missing values
{
"value": null
}Typical Use Cases
API Payloads
Validate REST API request and response bodies:
{
"userId": 123,
"action": "update",
"data": {
"email": "user@example.com",
"preferences": {
"notifications": true,
"theme": "dark"
}
}
}Configuration Files
Lint package.json, tsconfig.json, and other config files:
{
"name": "my-project",
"version": "1.0.0",
"scripts": {
"build": "tsc",
"test": "jest"
},
"dependencies": {
"express": "^4.18.0"
}
}CI/CD Settings
Validate GitHub Actions JSON expressions, AWS CloudFormation, and more:
{
"AWSTemplateFormatVersion": "2010-09-09",
"Resources": {
"MyBucket": {
"Type": "AWS::S3::Bucket",
"Properties": {
"BucketName": "my-bucket"
}
}
}
}Database Documents
Lint MongoDB documents, Elasticsearch queries, and NoSQL data:
{
"_id": "doc123",
"type": "user",
"profile": {
"name": "John Doe",
"tags": ["admin", "developer"]
},
"createdAt": "2024-01-15T10:30:00Z"
}JSON vs JavaScript Objects
JSON is not the same as JavaScript objects. Key differences:
| Feature | JSON | JavaScript |
|---|---|---|
| Keys | Must be double-quoted | Can be unquoted |
| Strings | Double quotes only | Single or double quotes |
| Comments | Not allowed | Allowed |
| Trailing commas | Not allowed | Allowed (ES5+) |
| Functions | Not allowed | Allowed |
Privacy & Security
All processing happens directly in your browser:
- No Server Communication: Your JSON data never leaves your device
- No Storage: Nothing is saved to localStorage, cookies, or servers
- Open Source: All code is transparent and auditable
Related Tools
Explore our other DevOps tools:
- YAML Linter - Validate YAML syntax and structure
- YAML/JSON Path Tester - Test JSONPath expressions
- kubectl Builder - Visual kubectl command builder
- JWT Tools - Decode and create JSON Web Tokens
Need help? All code is open-source. Visit our GitHub or contact us with questions or feedback.