JSON Formatter & Validator — Beautify and Validate JSON Online
Format · Minify · Validate · Schema · Tree View · AI Explain — 100% Browser, No Upload
What is a JSON Formatter?
A JSON Formatter converts raw, compressed, or unreadable JSON into properly indented, human-readable format. CalcNation's JSON Formatter works entirely in your browser — no installation, no login, and no data ever sent to any server.
All Features
Format — Beautify with 2/4/8 space indent. Minify — Compress and show size reduction %. Validate — Check syntax with exact error line & column. Schema — Validate against a JSON Schema. Tree View — Collapsible tree with search and copy path. Sort Keys A-Z — Normalise key order recursively. AI Explain — Plain-English description of your JSON. Import File — Drag & drop or pick .json/.txt up to 5 MB. Share URL — Shareable link with state in URL params.
Frequently Asked Questions
What is a JSON Formatter?
A JSON Formatter converts compressed or unreadable JSON into properly indented, human-readable format. It validates syntax and reports exact error line and column numbers. CalcNation's formatter runs 100% in your browser.
How to use JSON Formatter online?
Paste JSON in the left panel — it formats in real time. Use Format for readable output, Minify to compress, Validate to check errors, or Schema to validate against a JSON Schema.
Is this JSON Formatter free?
Yes, completely free with no limits. All processing happens in your browser — your data is never sent to any server.
Is my JSON data safe?
Yes. 100% browser-side. No upload, no storage, no server. Works offline once the page loads.
What is Sort Keys A-Z?
Sort Keys A-Z reorders all object keys alphabetically (recursively) before formatting. Useful for normalising API responses or comparing two JSON objects.
What is JSON Schema validation?
JSON Schema is a standard to define the shape of JSON data — which fields are required, their types, and constraints. Switch to Schema mode, paste a schema, and the validator tells you exactly which fields fail.
What does AI Explain do?
AI Explain uses Claude AI to describe the structure of your JSON in plain English — useful when working with unfamiliar API responses or complex nested data.
How to validate JSON errors?
Switch to Validate mode or paste invalid JSON — the tool shows the exact line and column where the error occurs.