Cookie header to JSON converter
Helps when debugging sessions and logins and checking what the browser sends with each request.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter cookie header and decode %xx in values.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
The Cookie: prefix is removed, the header is split on ; and each part at the first = into name and value, surrounding double quotes are removed as RFC 6265 allows, then %XX is decoded if the option is on.
Example
Inputs: Decode %XX in values = yes. Result: JSON: { "session_id": "abc123", "theme": "dark", "lang": "ar", "cart": "{\"items\":2}" }; Cookies: 4; Duplicate names skipped: 0.
Cookie: session_id=abc123; theme=dark; lang=ar; cart=%7B%22items%22%3A2%7D
{
"session_id": "abc123",
"theme": "dark",
"lang": "ar",
"cart": "{\"items\":2}"
}Limits and caveats
- When a name repeats the first value is kept, which is what most libraries read, and the duplicates are counted.
- Parts without an = sign are ignored.
Questions about this tool
Why can a cookie name repeat?
The browser sends two cookies with the same name when their path or domain differ, putting the more specific one first.
Should I decode the values?
Turn it on when values are %XX-encoded, and off to see each value exactly as sent.
Does this work for Set-Cookie headers?
No. Set-Cookie comes from the server with attributes such as Path and Expires, and has its own tool in this section.