Free JSON tools: view, fix, compare and convert
Paste once and keep going. Repair broken JSON, format it, compare two versions, query it with JSONPath, and export it to CSV, Excel or TOON. Everything runs in your browser, so your data stays with you.
Popular workflows
Fix a broken API response
Copied JSON that will not parse? Repair it, tidy it, then explore it.
What changed between two payloads?
Compare before and after, then query the parts you care about.
Get API data into a spreadsheet
Flatten the nesting, then export CSV or a multi-sheet Excel file.
Shrink data for an LLM prompt
Check what makes it big, then convert it to TOON.
Dig through a log file
Open JSONL logs as a table, fix the bad lines, check the size.
View
Fix & format
Compare
Query & transform
Convert
Analyze
Why JsonSnacks
Private by design
Parsing, repairing, converting and exporting all happen in your browser tab. Nothing you paste is sent to a server.
Live results
No Convert button. Output updates as you type, and panes can be dragged to the size you like on desktop.
One place for the whole job
Send your JSON from one tool to the next without pasting it again. Light and dark themes included.
Frequently asked questions
What is JsonSnacks?
JsonSnacks is a set of free online JSON tools: a viewer, formatter, repair tool, diff, JSONPath tester, flatten and unflatten, converters to CSV, Excel and TOON, a size analyzer and a JSONL viewer.
Is JsonSnacks free, and do I need an account?
It is free and needs no sign-up. The site is supported by a few clearly marked ads.
Is my JSON uploaded to a server?
No. Every tool runs in your browser, so the JSON you paste or open stays on your device.
Which tool should I use to fix invalid JSON?
Use JSON Repair. It fixes single quotes, trailing commas, comments, unquoted keys, Python values and missing brackets, and lists each change.
Can I use JsonSnacks for large files?
Yes, within your browser's memory. The viewer draws only the branches you open, and the JSONL viewer reads up to 200,000 lines. Very large files work best on a desktop browser.
What is TOON and why convert JSON to it?
TOON is a compact text format for the same data as JSON. It often uses fewer tokens in language model prompts, especially for lists of similar records. The JSON to TOON tool shows the size difference for your data.