Loading tool...
Format, validate XML with XPath queries, interactive tree view, XML-to-JSON conversion, and multiple color themes
Format, validate, and convert between YAML and JSON formats. Live validation, syntax highlighting, and bidirectional conversion.
Generate JSON Schema from JSON data automatically. Infers types, formats (email, date, URI), required fields, nested objects, and arrays. Supports Draft-07 and 2020-12.
The JSON Formatter & Validator is a powerful tool for working with JSON data, essential for developers debugging APIs, managing configurations, and handling JSON-based data. JSON has become the standard data format for web APIs, configuration files, and data interchange across systems, yet JSON from APIs and logs is often minified or poorly formatted, making it difficult to read and debug. This tool automatically detects whether your JSON is valid or malformed, displaying clear error messages that pinpoint exactly where syntax issues occur—missing commas, unmatched brackets, invalid character escapes, and more. The formatter reformats messy JSON into readable, properly indented code with your choice of indentation style (2 spaces, 4 spaces, or tabs). One-click minification removes all whitespace and formatting to produce compact JSON suitable for production use, reducing file size by 30-50% depending on original formatting. The interactive tree view lets you explore complex nested JSON structures visually, expanding and collapsing sections to navigate large datasets. JSONPath query support enables extracting specific values from complex JSON objects without parsing manually. All processing happens entirely in your browser using standard JSON parsing and formatting, ensuring complete privacy—your data never leaves your device.
Format and validate API responses to understand data structure, identify missing fields, and debug integration issues with external APIs.
Convert minified configuration JSON into readable format for editing, review, and understanding application settings.
Validate and format JSON payloads before sending to APIs, catching syntax errors that would cause API rejections.
Navigate complex, deeply nested JSON structures using the interactive tree view, making large datasets easier to understand and analyze.
Remove all whitespace and formatting from JSON for production use, reducing file size and improving transmission efficiency.
Format JSON to understand how it maps to JavaScript objects, and generate JavaScript code from JSON structures.
JSON (JavaScript Object Notation) is formally defined by RFC 8259, published in December 2017 as an Internet Standard, superseding earlier specifications RFC 7159 and RFC 4627. Despite its name referencing JavaScript, JSON is a language-independent data format with parsers available in virtually every programming language. The specification is remarkably concise — the entire grammar fits on a single page — defining just six data types: strings, numbers, booleans (true/false), null, objects (unordered key-value collections), and arrays (ordered value sequences).
JSON's design reflects deliberate constraints that contribute to its success. Douglas Crockford, who popularized JSON in the early 2000s (though the format existed implicitly in JavaScript since 1999), described it as "the intersection of modern programming languages" — using only data structures that every language supports. Unlike XML, JSON has no attributes, no comments (a controversial omission), no processing instructions, and no schema language built into the format. Numbers follow IEEE 754 double-precision floating-point representation, which means JSON cannot natively represent arbitrary-precision integers — a limitation that has caused real bugs when JavaScript parses 64-bit integer IDs from other systems, silently losing precision beyond 2^53.
The rise of JSON over XML for web APIs is one of the most significant shifts in data interchange history. XML dominated the early 2000s through SOAP web services, but its verbosity (closing tags repeat element names, attributes require special handling) and complexity (namespaces, DTDs, processing instructions) created friction for web developers. JSON's advantage was not just syntactic brevity but direct mapping to JavaScript objects, eliminating the parsing layer that XML required. By 2012, JSON had overtaken XML in new API designs, and today over 90% of public REST APIs use JSON as their primary format.
JSON parsing is a straightforward recursive descent process that maps directly to the grammar. A conforming parser must handle several subtle requirements: strings must use double quotes (single quotes are invalid), keys must be strings (not bare identifiers), trailing commas are forbidden, and the specification mandates UTF-8 encoding (RFC 8259 made this explicit, resolving ambiguity in earlier drafts). The \/ escape sequence (escaped forward slash) is valid but unnecessary — a historical artifact from JSON's use in HTML script tags where </ would prematurely close the tag.
JSON's limitations have spawned several extensions and alternatives. JSON5 adds comments, trailing commas, unquoted keys, and other syntactic conveniences. JSONC (JSON with Comments) is used by VS Code configuration files. JSON Lines (JSONL) places one JSON value per line for streaming and log processing. MessagePack and CBOR provide binary-encoded equivalents for performance-critical applications, reducing both size and parsing time compared to text-based JSON while preserving the same data model.
The validator highlights exactly where the error is, showing the line number and describing what's wrong (missing comma, unmatched bracket, etc.).
Yes, the tool handles large JSON files efficiently. For very large files (50MB+), processing may take a few seconds depending on your device.
JSONPath is a query language for JSON, similar to XPath for XML. It lets you extract specific values from JSON using expressions like $.store.book[0].title
All processing happens directly in your browser. Your files never leave your device and are never uploaded to any server.