CodePen
codepen.io
Write HTML, CSS and JavaScript in a tab and watch it render live
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jsoncrack.com
Turns a wall of JSON into a node graph you can pan and search.
Paste JSON, YAML, XML or CSV and it draws the structure as a linked graph you can collapse, search and export as an image — far faster than scrolling a 4,000-line API response hunting for one nested key. It converts between those formats too. Everything runs on your device with nothing stored on their servers, and the practical ceiling is around 300 KB of data before the graph starts to crawl.
AltFTool does this too
If you would rather not leave the site, JSON Formatter covers the same job here — free, no account, and it runs in your browser.
Open JSON FormatterQuestions
A genuinely usable free tier with paid plans for volume or team features. The graph bogs down past roughly 300 KB of input, and the advanced editing features moved to a paid sibling product.
No. JSON Crack does the work inside your browser, so the file never leaves your device — you can load the page, disconnect from the network, and it still works. That makes it a reasonable choice for material containing personal data.
The graph bogs down past roughly 300 KB of input, and the advanced editing features moved to a paid sibling product.
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