JSON to Cookie header converter
Useful for replaying a session in Postman, curl or an automated test from cookies saved as JSON.
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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 json, percent-encode values and add the cookie: prefix.
- 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
Each key and value become name=value, joined by a semicolon and a space. With encoding on, the value goes through encodeURIComponent; without it the value is checked for spaces, ", comma, ; and \, which RFC 6265 does not allow.
Example
Inputs: Percent-encode values = yes, Add the Cookie: prefix = no. Result: Cookie header: session_id=abc123; theme=dark; lang=ar; Cookies: 3.
{"session_id": "abc123", "theme": "dark", "lang": "ar"}session_id=abc123; theme=dark; lang=ar
Limits and caveats
- Cookie names must be HTTP tokens, so spaces or characters such as = and ; in a name give an error.
- Nested objects or arrays are not accepted as values; turn them into text first.
Questions about this tool
Do I need to encode the values?
Yes when they contain spaces, commas or Arabic text, which a cookie value cannot hold unencoded.
How do I use the result with curl?
Put it in quotes after -b, or turn on the prefix and pass it with -H.
Are attributes such as Path and Expires supported?
No. Those belong to Set-Cookie sent by the server; a Cookie header carries only names and values.