Where is JSON formatting used?
API Development
Format and validate API request/response bodies during development and debugging of REST or GraphQL APIs.
Config Files
Beautify JSON configuration files for tools like package.json, tsconfig.json, .prettierrc, and many more.
Database Exports
Format JSON exports from MongoDB, Firebase, DynamoDB, and other NoSQL databases for readability.
Log Analysis
Beautify minified JSON log entries from services like Datadog, Splunk, or CloudWatch for easier reading.
Mobile Development
Validate JSON payloads exchanged between mobile apps and backend servers during testing.
AI & ML Data
Format training datasets, model configurations, and AI API responses from OpenAI, Gemini, and others.
JSON Data Types — Complete Reference
JSON supports exactly 6 data types as defined in RFC 8259. Understanding these types is essential for writing valid JSON.
| Type | Valid Syntax | Example in JSON |
|---|---|---|
| String | "Hello, World!" | "name": "Alice" |
| Number | 42 or 3.14 | "age": 30 |
| Boolean | true or false | "active": true |
| Null | null | "email": null |
| Object | { "key": value } | "address": { "city": "Dubai" } |
| Array | [ value, value ] | "tags": ["js", "api"] |
Common JSON Errors & How to Fix Them
These are the most frequent mistakes that make JSON invalid. Our validator detects all of these and shows clear error messages.
{"a": 1, "b": 2,}{"a": 1, "b": 2}{'name': 'Alice'}{"name": "Alice"}{name: "Alice"}{"name": "Alice"}{"val": undefined}{"val": null}{"a": 1 "b": 2}{"a": 1, "b": 2}{"items": [1, 2}{"items": [1, 2]}JSON vs XML vs YAML — Which Should You Use?
JSON (JavaScript Object Notation) is the dominant data interchange format for web APIs and modern applications. It is lightweight, human-readable, and natively supported by JavaScript. JSON supports nested objects and arrays, making it highly flexible for complex data structures.
XML (eXtensible Markup Language) is more verbose but supports attributes, namespaces, and schemas. It remains popular in enterprise, SOAP web services, and legacy systems. XML is harder to read and parse compared to JSON.
YAML (YAML Ain't Markup Language) is the most human-readable of the three and is commonly used for configuration files (Docker Compose, Kubernetes, GitHub Actions). However, YAML is indentation-sensitive, making it error-prone. For APIs and data transmission, JSON is the clear winner due to its simplicity and universal browser support.