What is JSON?

JSON is an acronym for JavaScript Object Notation. It was originally discovered in the early 2000s by Douglas Crockford, one of the architects of JavaScript. JSON is composed of two data structures: An ordered list expressed using "[]" (square brackets) and a collection of key/value pairs which is expressed using "{}" (curly brackets). JSON is considered a data interchange format intended for language-independent usage as a format which is easily composable and readable by humans. The JSON file format is often used as a simpler alternative to XML, as it requires fewer characters and leads to fewer human errors. Today, JSON use is ubiquitous in web and mobile applications to exchange data. Both REST and GraphQL use JSON exclusively, as a way to communicate data between applications.

JSON and Comments

One important characteristic of JSON is that it does not support comments. The JSON specification intentionally excludes comments to keep the format simple and unambiguous. Douglas Crockford, the creator of JSON, made this design decision to prevent people from using comments to include parsing directives or other metadata that could break interoperability between systems.

However, in practice, many developers want to add comments to their JSON configuration files. This led to the creation of JSONC (JSON with Comments), a superset of JSON that extends the format to allow both single-line (//) and multi-line (/* */) comments. JSONC is widely used in configuration files, particularly in Visual Studio Code settings files (settings.json) and TypeScript configuration files (tsconfig.json). While JSONC is not part of the official JSON standard, many modern JSON parsers and tools provide support for it as an optional feature.

About JSON Checker

The perfect JSON validation and formatting tool would be fast, simple, intuitive, and beautiful. This is exactly what JSON checker aims to be. JSON checker allows users to input their JSON and quickly check for malformed JSON, fix the issue, and beautify the JSON into a more readable format. When you copy paste your JSON the built-in JSON formatter will autoformat/beautify valid JSON. If your JSON is invalid, we provide clear and concise error messages pointing to a specific line number for you to validate and fix. The tool provides JSON syntax highlighting, to help with readability.

JSON Checker Features

  • Helpful error messages to help identify invalid or incorrect JSON syntax. Validation and error messages will display directly beneath the editor.
  • Instant validation as you compose JSON in the editor.
  • Copy and Paste JSON directly into the editor to have it formatted and validated instantly.
  • Easily collapse and expand sections of your JSON document, allowing you to focus on specific parts of your code and navigate complex files more effectively.
  • Benefit from real-time bracket matching that instantly highlights corresponding brackets as you edit, helping to quickly identify and correct syntax errors.

JSON Alternatives