Developer Tools
JSON Formatter
& Validator
The most complete free JSON tool. Format, minify, validate, and analyse any JSON instantly — with syntax highlighting, precise error detection, path explorer, and live statistics.
Format & beautify with custom indent (2, 4 spaces or tabs)
Minify JSON to the smallest possible size
Validate with exact error location & fix suggestions
Syntax highlighting — keys, strings, numbers, booleans
Path explorer: browse every key/value with dot-notation paths
Live stats: depth, keys, arrays, size, type counts
// JSON Summary
JSON Input & Output
Input JSON
0 chars
Samples:
Output 0 chars
Formatted output will appear here…
⚠ JSON Parse Error
Message
Position
Context
Fix hint
JSON Data Types Reference
| Type | Example | Notes |
|---|---|---|
| String | "Hello, world" | Must use double quotes |
| Number | 42, 3.14, -1e5 | Integer or float, no quotes |
| Boolean | true, false | Lowercase only |
| Null | null | Represents absence of value |
| Object | {"key": "value"} | Unordered key-value pairs |
| Array | [1, "two", true] | Ordered list of any values |
Common JSON Errors & Fixes
| Error | Cause | Fix |
|---|---|---|
| Unexpected token | Invalid character | Check for single quotes, trailing commas |
| Unexpected end | Unclosed bracket/brace | Count opening/closing {[ |
| Trailing comma | Comma after last item | Remove comma before } or ] |
| Single quotes | Used instead of double | Replace 'key' with "key" |
| Comments | JSON has no comments | Remove // … or /* … */ |
| Unquoted keys | JS style not valid | Add double quotes around keys |
| NaN / Infinity | Not valid JSON values | Use null or a number string |
JSON Formatting & Validation Guide
JSON (JavaScript Object Notation) is the universal data interchange format used by virtually every web API, configuration file, and database. Properly formatted JSON is easier to read, debug, and maintain. Valid JSON follows the RFC 8259 standard — strict rules about syntax that differ from JavaScript object literals.
What is the difference between JSON format and JSON validation?
JSON formatting (beautifying) adds consistent indentation and line breaks to make JSON human-readable, without changing the data. JSON validation checks whether the text is syntactically correct according to RFC 8259 — for example, verifying all keys are quoted, no trailing commas, and all brackets are properly closed. A JSON file can be valid but poorly formatted, or invalid and need fixing before it can be parsed.
Why do trailing commas cause JSON errors?
Unlike JavaScript, JSON strictly forbids trailing commas — a comma after the last element in an object or array. For example, {"name":"Alice",} is invalid JSON. This is a common mistake when manually editing JSON. Most parsers throw "Unexpected token }" or "Unexpected token ]". The fix is simply to remove the comma before the closing bracket or brace.
What is JSON minification and when should I use it?
JSON minification removes all unnecessary whitespace (spaces, tabs, newlines) to produce the smallest possible valid JSON string. This reduces file size and bandwidth for API responses, configuration storage, and data transfer. For a 10KB formatted JSON file, minification typically reduces it by 30–50%. Use minified JSON in production APIs; keep formatted JSON for configuration files humans need to read and edit.
Can JSON contain comments?
No — standard JSON (RFC 8259) does not support comments. JSON was intentionally designed without comments to keep it simple and universally parseable. If you need comments, use JSON5, HJSON, or TOML, which are comment-aware supersets. For configuration files that need annotations, consider YAML. To work around the limitation in standard JSON, some tools use a special "_comment" key convention, though this adds unnecessary data.
What is a JSON path and how do I use it?
A JSON path is a dot-notation expression that identifies a specific value within a JSON structure. For example, in {"user":{"name":"Alice","scores":[95,87]}}, the path user.name returns "Alice" and user.scores[0] returns 95. JSONPath (RFC 9535) extends this with wildcards ($..name), filters, and recursive descent. Paths are used in APIs, database queries (MongoDB, PostgreSQL jsonb), and tools like jq for command-line JSON processing.
What is the maximum JSON nesting depth?
The JSON specification (RFC 8259) does not define a maximum nesting depth, but parsers impose practical limits. Most environments allow 20–512 levels: Python's json module defaults to 128, many browsers and Node.js handle 1000+. However, deeply nested JSON (beyond 10–15 levels) is often a design smell — consider flattening the structure. Very deep nesting also increases parse time and stack usage exponentially.
More Free Online Tools
Simple tools. Surgical fixes. Zero friction.
Amazon Connect CCP Log Parser
Parse Amazon Connect CCP logs into structured, searchable diagnostics.
OpenAmazon Connect Agent Workstation Validator
Pre-flight check for Amazon Connect softphone agents.
OpenAmazon Connect Pricing Calculator
Instantly estimate monthly AWS Connect costs — voice, chat, email, campaigns, telephony & more.
OpenConnect CloudWatch Log Analyzer
Drop any Amazon Connect CloudWatch log and get a rich visual breakdown.
Open