RubanTools

JSON Validator

Paste your JSON and get instant validation - errors shown with context, plus a summary of keys, values and depth.

Paste JSON

JSON Validator and Formatter

JSON (JavaScript Object Notation) was formalised by Douglas Crockford in the early 2000s and became an ECMA standard (ECMA-404) in 2013. It is now the dominant data interchange format for web APIs, surpassing XML in most modern applications. JSON's lightweight, human-readable structure - built around key-value pairs, arrays, and nested objects - makes it ideal for REST APIs, configuration files, and database query results. A single misplaced comma, missing quotation mark, or incorrect bracket can render an entire JSON payload invalid, causing application failures that are often difficult to debug without proper tooling.

JSON in India's Tech Ecosystem

India's IT services sector, contributing approximately 7.5% of GDP and employing over 5 million professionals as of 2024, works extensively with JSON APIs daily. Backend developers at companies like Infosys, Wipro, TCS, and thousands of product startups in Bengaluru, Pune, and Hyderabad regularly debug JSON from third-party APIs including payment gateways (Razorpay, PayU), logistics providers (Delhivery, Shiprocket), and government APIs such as GST NIC portals and Aadhaar OTP APIs. The JSON:API specification and OpenAPI 3.0 - both JSON-based standards - are widely adopted in Indian enterprise software development.

How This Tool Works

Paste any JSON string into the validator to instantly check for syntax errors. Valid JSON is automatically pretty-printed with proper indentation for readability. Common errors caught include trailing commas (not allowed in standard JSON), single-quoted strings, unescaped special characters, and mismatched brackets - all highlighted with line-specific error messages to speed up debugging.

JSON Validator Questions

JSON (JavaScript Object Notation) is a lightweight data format used to exchange data between APIs and services. Even a single misplaced comma, unquoted key, or unclosed bracket makes the entire JSON unparseable. A JSON validator checks syntax and pinpoints errors so developers can fix them quickly.

The most common JSON errors: (1) Trailing commas - JSON does not allow a comma after the last item. (2) Single quotes - JSON requires double quotes. (3) Unquoted keys - JSON keys must always be in double quotes. (4) Missing commas between items. (5) Unclosed braces or brackets.

JSON is a strict text-based format: all keys and strings must be in double quotes; trailing commas are not allowed; undefined, functions, and comments are not supported. A JavaScript object is more permissive - it allows single quotes, trailing commas, and shorthand property names.

'Unexpected token' means the parser found a character it did not expect. Common causes: single quotes instead of double quotes, a comma after the last property, a missing colon between key and value, or an extra closing brace. Paste your JSON in our validator - it shows the exact error location.

Yes - validation runs entirely in your browser using JavaScript's built-in JSON.parse(). Your data is never sent to any server. This makes it safe for validating API credentials, configuration files, or any sensitive JSON content.