Is there any way to send arbitrary json key-value paid inside a http request but outside the usual body , fields? I've been fiddling with postman and httpbin.org/post, didn't manage but now I'm wondering if that is just a limitation of Postman.data or json
Is it possible to directly receive in, e.g. express.js req.username?
Data or json fields? No such thing. There is a header and body. You can pass data in the header if you so pleased but that's not really what the header is for. And no you can not do req.username unless you have some sort of middle ware before the route that does that for you.