About
Three formats exist for the same data and different tools insist on different ones. Paste whichever you have and export whichever you need. The conversion runs in the page, which matters because cookies are usually session credentials.
How to use
Paste an HTTP cookie header, a JSON array, or the contents of a cookies.txt file, then pick the output format. Clear the box afterwards.
Three formats and who wants which
The header form is the one you copy out of a browser's network tab, and it is names and values separated by semicolons. The JSON array is what extensions and automation libraries produce, and it carries the metadata. The Netscape file is a tab separated layout that download tools have expected for decades. Nothing is wrong with any of them, they simply grew up in different places.
What conversion cannot recover
Going from a rich format to a poor one loses information permanently. The header form has no place for the expiry date, the domain, the path, or the secure and HttpOnly flags, so those fall away. Converting back produces entries with plausible defaults filled in, and a tool that needed the real domain will fail in a way that looks like the cookies are wrong. Keep the richer export if you might need it twice.
The tab separated file, field by field
A Netscape line holds the domain, a flag for whether subdomains are included, the path, whether the cookie is HTTPS only, an expiry as a Unix timestamp, then the name and the value. The separators are tabs, not spaces, which is the single most common reason a hand edited file is rejected. An expiry of zero means the cookie was a session cookie with no stored lifetime.
These are credentials
A session cookie is the logged in state itself. Anyone holding it is signed in as you until it expires or the session is revoked, without needing a password or a second factor. That is why this conversion runs locally and why the input box is worth clearing. Do not paste someone else's cookies here, and do not paste your own into a service that processes them on a server.
FAQ
Why does it say the input is not recognised?
Usually a mix of two formats in one paste, or a JSON array missing the name and value fields. Paste one format at a time.
What still uses the Netscape format?
Download tools and command line clients that read a cookies.txt file. It is tab separated and old, and a fair number of programs still expect exactly it.
Are the cookies transmitted?
No. The conversion happens in your browser, which is deliberate given what is usually in them.
Some fields disappeared after converting.
The header form carries names and values only. Converting from a richer format to it drops expiry, domain, path, and flags, and converting back cannot invent them again.
Related tools
- Developer and text tools
- HTTP Header Checker
Read the response headers a URL returns.
- JSON Formatter
Format, minify and check JSON in the browser.
- URL Encoder and Decoder
Percent encode or decode text, locally.
- Unix Timestamp Converter
Convert between epoch timestamps and dates.
- User Agent Parser
Break a UA string into browser, OS and device.
- List Text Cleaner
Deduplicate, sort and tidy a pasted list.