[BLOCK QUOTE].

Yeah, I was wrong, sorry.
I'm not familliar with Deno and it seems like the "value" propery is just the way the framework your using parses the body.
But, If I may have another assumption, you probably need to provide a "content-type" header when making your post request to the server on [TRIPLE QUOTE]., like so:
[TRIPLE QUOTE].
It should tell the body parser to treat the request's body as json.