What's your expected output? Because here it kind of looks like you want:

{
   "mike":20,
   "johndeo@/test.com":test
}
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which doesn't make much sense.

One easy way to make json structure in perl, is to simple encore perl structures using JSON:

use JSON;
my %data = (name => "Mike", age => 20, email => "mike@perlmonks.org", 
+pass => "IAmGroot");
print encode_json(\%data); #edited thanks to marto
__DATA__
{"age":20,"pass":"IAmGroot","email":"mike.org","name":"Mike"}
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NB: be careful with double quotes, @ should be interpreted as the sigil of an array variable, even though here it is not for some reason. Simple quotes would be better.

Edit: the fact that @/ (a punctuation variable) is not interpolated is actually documented in perlop

"Punctuation" arrays such as @* are usually interpolated only if the name is enclosed in braces @{*}, but the arrays @_ , @+ , and @- are interpolated even without braces.