If I understand you correctly, you're suggesting something like this:

use strict;
use warnings;
use JSON;
use URI::Escape;

my $json_string = JSON::to_json($perl_structure);
print URI::Escape::uri_escape($json_string);
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Output:

%7B%22sub%22%3A%7B%22name%22%3A%22foo%22%2C%22message%22%3A%22bar%22%7D%2C%22file_ids%22%3A%5B1%2C2%5D%2C%22name%22%3A%22test%20name%22%7D

So that's kind of like saying:

https://example.com/api/v1/dosomething?{"file_ids":[1,2],"name":"test name","sub":{"message":"bar","name":"foo"}}

and I need to be saying:

https://example.com/api/v1/dosomething?name=test+name&file_ids[]=1&fil
+e_ids[]=2&sub[name]=foo&sub[message]=bar
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I did take a look at the URI module and I didn't see anything there...

Cheers,

Brent