How it works
How to use the JSON URL Decode
Paste your input
Paste the percent-encoded string.
Decode
The decoded JSON is pretty-printed automatically.
Copy the result
Use Swap to reverse the direction.
Percent-encoding in a nutshell
URLs may only contain a limited set of ASCII characters. Everything else — spaces, quotes, braces, non-ASCII letters — is written as %XX bytes of its UTF-8 encoding. encodeURIComponent encodes every reserved character, which is what you need for query parameter values.
Built for developers
Why developers use it
Private by design
Runs 100% in your browser. Nothing you paste is uploaded, logged or stored on a server.
Instant results
Output updates as you type, with precise error locations when something is wrong.
Works offline
Once loaded, the tool keeps working without a connection. Install it as an app if you like.
Free, no sign-up
No accounts, no limits, no watermarks.
FAQ
Frequently asked questions
Should I use + or %20 for spaces?
Form submissions (application/x-www-form-urlencoded) use +; everywhere else in a URL, %20 is correct.
Is my data uploaded anywhere?
No. Everything runs locally in your browser — nothing you paste or open is sent to a server, logged or stored. The tool keeps working offline once the page has loaded.
Keep going
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