JSONForge
JSON Formatter, Validator & Diff Tool
Format, validate, compare, and explore JSON data. Tree view, diff mode, syntax highlighting. Free, private — runs entirely in your browser.
{
"name": "Infinity AI",
"type": "Organization",
"projects": [
{
"name": "Neuromantix",
"modules": 108,
"language": "Rust",
"loc": 84000
},
{
"name": "Vitalis",
"modules": 345,
"language": "Rust",
"loc": 196000
},
{
"name": "Void LLM",
"params": "303M",
"language": "Rust + CUDA",
"tokPerSec": 7800
}
],
"stats": {
"totalLOC": 347000,
"totalTests": 8206,
"rustVsPython": "139x faster"
},
"url": "https://infinitytechstack.uk",
"active": true
}Why JSONForge?
Format & Beautify
Transform messy, minified JSON into beautifully indented, readable code. Configurable indentation with 2, 4, or 8 spaces.
Live Validation
Get immediate validation feedback with parser error context to help locate syntax issues faster.
6 Example Templates
Load realistic example data for REST APIs, package.json, GeoJSON, CloudConfig, GraphQL, and more. Learn JSON structure by example.
Tree View Explorer
Navigate complex JSON structures with our visual tree view. See keys, types, and values at every nesting level at a glance.
JSON Diff Compare
Paste two JSON objects side-by-side to see highlighted differences for API debugging and config comparison.
Size Comparison
See formatted vs minified byte counts and compression savings. Know exactly how much whitespace your JSON contains.
Browser-Local Processing
Core formatting and validation run in your browser via native JSON.parse/stringify. Avoid pasting sensitive secrets.
Export & Share
Copy formatted JSON to clipboard or download as a .json file. Ready to use in your codebase, API, or configuration.
Common Use Cases
API Development
Format and inspect REST API responses. Debug payloads, validate response shapes, and compare API versions side-by-side with diff mode.
Package Management
View and edit package.json, tsconfig.json, and other config files. Validate syntax before committing to version control.
GeoJSON & Mapping
Format and validate GeoJSON for mapping applications. Inspect coordinates, feature properties, and geometry types.
Cloud Configuration
Validate cloud infra configs (Terraform, AWS, Docker Compose). Catch syntax errors before deploying to production.
GraphQL Debugging
Inspect GraphQL responses, format query results, and compare mutations. Tree view makes deeply nested data easy to navigate.
Testing & QA
Compare expected vs actual JSON outputs. Diff mode highlights exactly what changed between test runs or API versions.
Frequently Asked Questions
Is JSONForge free to use?
Yes, JSONForge is entirely free, requires no account, and runs entirely in your web browser for maximum privacy.
Is my JSON data sent to a server?
No. All formatting, validation, and diffing happens locally in your browser. Your data is never uploaded to any server, ensuring complete security and privacy.
What does the JSON Diff tool do?
The JSON Diff tool allows you to paste two JSON payloads and see a side-by-side comparison of the exact additions, deletions, and modifications between them.
Does JSONForge support AI Agent schemas and MCP server manifests?
Yes. JSONForge includes built-in presets for Model Context Protocol (MCP) Server Cards (2026 specification) and OpenAI Agents API schemas, allowing AI and SOE/AOE engineers to validate tool definitions and telemetry manifests client-side.