Debugging an API response
Before
One-line JSON, 14,000 characters
After
Beautified with 2-space indent, easy to scan
Found the missing comma in under 30 seconds. Manually, this would have taken 10 minutes.
All Tools
JSON Formatter & Validator – Beautify, Validate, Minify
I built this after one too many times copy-pasting a minified API response into a scratch file and squinting at it. Paste your JSON, hit Beautify, and read it properly. Hit Minify before you send it to production. Nothing gets uploaded.
100% free, no signup
Valid JSON
Your files are processed in your browser and never uploaded to any server.
A note from me
I debug API responses with this daily. My tip: when a JSON file won't validate, the error is almost always a trailing comma or a missing quote on a key. Both look fine at a glance — the validator catches them in one pass. For large files over 5 MB, Chrome handles it fine, but Safari sometimes slows down.
— Mirza Noman Baig
How to use this tool
- 1Paste your JSON into the editor.
- 2Click Beautify to add indentation and line breaks.
- 3Click Minify to strip whitespace before sending to production.
- 4Pick your indent style — 2 spaces, 4 spaces, or tab.
- 5If something's broken, the validator tells you exactly where.
Real results from testing
These are actual measurements from using this tool, not estimates.
Preparing a payload for production
Before
Beautified JSON, 8.2 KB
After
Minified, 4.1 KB
Cut the payload size roughly in half. Useful when you're sending thousands of requests.
Validating a config file
Before
config.json that 'looked right' but the app wouldn't boot
After
Validator flagged a trailing comma on line 47
One character was breaking the whole app. The validator caught it instantly.
JSON Formatter & Validator features
Beautify and validate
Turn minified JSON into readable, well-indented output — and catch syntax errors instantly.
Minify for production
Strip whitespace to reduce payload size before sending through APIs.
Custom indentation
Choose 2 spaces, 4 spaces, or tabs to match your project's style.
Runs entirely in your browser
Your data never gets uploaded. Safe for API keys and sensitive payloads.
Frequently asked questions
Is my JSON uploaded anywhere?+
No. Everything runs in your browser. Your API keys, tokens, and payloads never leave your device.
Does it support JSON with comments?+
No. Strict JSON doesn't allow comments or trailing commas. The validator will flag them as errors.
Can it fix invalid JSON automatically?+
No. It tells you exactly where the error is, but you have to fix it yourself. Auto-fixing risks changing your data.
How large a file can it handle?+
I've tested up to 10 MB. Chrome handles it fine. Safari can get sluggish above 5 MB.
Does minifying change my data?+
No. Minify only removes whitespace. All keys and values stay exactly the same.