jsonyo · JSON Swiss-Army Knife by vøiddo

jsonyo is a free JSON Swiss-Army Knife for your browser. Five JSON tools in one popup, zero data leaves your computer, zero ads, zero account.

WHAT IT DOES

• Format — paste any JSON, get pretty-printed output with proper indentation. Two-space, four-space, or tab. Toggle line numbers.
• Validate — instant syntax check with line + column pointing at exactly where the problem is. No more guessing what "Unexpected token U at position 1247" means.
• Query — run JSONPath expressions ($.users[*].name), filter, recursive-descend, slice arrays, project fields. Get back the matching subset.
• Diff — side-by-side comparison of two JSON documents. Added / removed / changed paths called out, no eyeballing arrays line-by-line.
• Minify — strip whitespace, get the smallest valid JSON. Useful for production payloads and HTTP body size budgets.
• Stats — count keys, depth, types, longest path, biggest array. Quick structural overview before deeper editing.

WHY USE IT

Most online JSON formatters paste your data into a server somewhere — sometimes the wrong server. jsonyo runs entirely in your browser. Your JSON never leaves your machine. Open the network tab — you will see no outbound traffic at all. The manifest is open source so you can verify it yourself.

PRIVACY

• Zero data collection
• Zero outbound network requests
• Zero analytics, zero tracking, zero cookies
• Zero account, zero login
• Zero host_permissions — works only when you click the icon
• Manifest V3, declares data_collection_permissions: ["none"] per Mozilla 2026 standard

The same engine powers our open-source npm CLI (@v0idd0/jsonyo) and our WordPress plugin. Single source of truth across all three surfaces, MIT-licensed, auditable.

KEYBOARD SHORTCUTS

• Ctrl/Cmd+B — format
• Ctrl/Cmd+M — minify
• Ctrl/Cmd+Enter — apply current tool
• Tab — insert two spaces

ABOUT DEVELOPER

Built by vøiddo — a small studio shipping AI-flavoured products, free dev tools, Chrome extensions and weird browser games. We make tools we want to use ourselves. Free forever. No upsell. No "Pro" tier.

Bug or feature request? support@voiddo.com — usually answered within 36 hours weekdays.