If there was issue of SSL certificate then why i am directly able to see the data in web browser when i browse the link https://www.cryptopia.co.nz/api/GetCurrencies in the web browser?

Hi, this is because your desktop browser uses the Certificate Authority root certificates that are distributed with your operating system, whereas LWP::UserAgent does not know about them. You can force LWP to use the same root certificates by setting the value of the environment variable HTTPS_CA_DIR to the location on your system.

On my system the certificate directory is /etc/ssl/certs.

Without:

use strict; use warnings;
use LWP::UserAgent;
use JSON;
use Data::Dumper;

my $url = "https://www.cryptopia.co.nz/api/GetCurrencies";
my $res = LWP::UserAgent->new->get( $url );
die $res->content if not $res->is_success;
print Dumper decode_json $res->decoded_content;
__END__
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Output:

$ perl 1206484.pl | head -20
Can't connect to www.cryptopia.co.nz:443 (certificate verify failed)

SSL connect attempt failed error:14090086:SSL routines:ssl3_get_server
+_certificate:certificate verify failed at /home/nick/perl5/perlbrew/p
+erls/perl-5.26.1/lib/site_perl/5.26.1/LWP/Protocol/http.pm line 46.
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Now with the UA pointed at the CA cert store:

use strict; use warnings;
use LWP::UserAgent;
use JSON;
use Data::Dumper;

BEGIN {
    $ENV{'HTTPS_CA_DIR'} = '/etc/ssl/certs';
}

my $url = "https://www.cryptopia.co.nz/api/GetCurrencies";
my $res = LWP::UserAgent->new->get( $url );
die $res->content if not $res->is_success;
print Dumper decode_json $res->decoded_content;
__END__
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Output:

$ perl 1206484.pl | head -20
$VAR1 = {
          'Message' => undef,
          'Success' => bless( do{\(my $o = 1)}, 'JSON::PP::Boolean' ),
          'Error' => undef,
          'Data' => [
                      {
                        'MaxWithdraw' => '90000000',
                        'IsTipEnabled' => bless( do{\(my $o = 0)}, 'JS
+ON::PP::Boolean' ),
                        'DepositConfirmations' => 20,
                        'Status' => 'OK',
                        'MinWithdraw' => '20000',
                        'Name' => '1337',
                        'Algorithm' => 'POS',
                        'Symbol' => '1337',
                        'MinBaseTrade' => '2e-05',
                        'StatusMessage' => undef,
                        'MinTip' => '166.66666666',
                        'ListingStatus' => 'Active',
                        'Id' => 331,
                        'WithdrawFee' => '0.01'
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Hope this helps!