diff --git a/lib/OpenQA/Setup.pm b/lib/OpenQA/Setup.pm
index 7071e165225..f5bf21581dd 100644
--- a/lib/OpenQA/Setup.pm
+++ b/lib/OpenQA/Setup.pm
@@ -363,7 +363,7 @@ sub setup_mojo_tmpdir () {
 
 sub load_plugins ($server, $monitoring_root_route = undef, %options) {
     push @{$server->plugins->namespaces}, 'OpenQA::WebAPI::Plugin';
-    $server->plugin($_) for qw(Helpers MIMETypes CSRF REST HashedParams Gru YAML);
+    $server->plugin($_) for qw(Helpers MIMETypes CSRF REST Gru YAML);
     $server->plugin('AuditLog') if $server->config->{global}{audit_enabled};
     # Load arbitrary plugins defined in config: 'plugins' in section
     # '[global]' can be a space-separated list of plugins to load, by
diff --git a/lib/OpenQA/WebAPI/Controller/API/V1/Table.pm b/lib/OpenQA/WebAPI/Controller/API/V1/Table.pm
index cac24d3b21d..85db599132a 100644
--- a/lib/OpenQA/WebAPI/Controller/API/V1/Table.pm
+++ b/lib/OpenQA/WebAPI/Controller/API/V1/Table.pm
@@ -354,10 +354,7 @@ sub _prepare_settings {
     my ($self, $table, $entry) = @_;
     my $validation = $self->validation;
     my $hp;
-    # accept both traditional application/x-www-form-urlencoded parameters
-    # with hash entries having key names encoded like settings[value1]
-    # (see doc at the end of HashedParams.pm)
-    # as well as modern application/json encoded hashes
+    # accept modern application/json encoded hashes
     my $error;
     if ($self->req->headers->content_type =~ /^application\/json/) {
         try {
@@ -377,7 +374,7 @@ sub _prepare_settings {
         $validation->input($hp);
     }
     else {
-        $hp = $self->hparams();
+        return 'Invalid request Content-Type ' . $self->req->headers->content_type . '. Expecting application/json.';
     }
 
     for my $par (@{$TABLES{$table}->{required}}) {
diff --git a/lib/OpenQA/WebAPI/Plugin/HashedParams.pm b/lib/OpenQA/WebAPI/Plugin/HashedParams.pm
deleted file mode 100644
index 8543f917a3f..00000000000
--- a/lib/OpenQA/WebAPI/Plugin/HashedParams.pm
+++ /dev/null
@@ -1,111 +0,0 @@
-package OpenQA::WebAPI::Plugin::HashedParams;
-use Mojo::Base 'Mojolicious::Plugin';
-
-our $VERSION = '0.04';
-
-sub register {
-    my ($plugin, $app) = @_;
-
-    $app->helper(
-        hparams => sub {
-            my ($self, @permit) = @_;
-
-            if (!$self->stash('hparams')) {
-                my $hprms = $self->req->params->to_hash;
-                my $index = 0;
-                my @array;
-
-                foreach my $p (keys %$hprms) {
-                    my $key = $p;
-                    my $val = $hprms->{$p};
-                    $val =~ s/\\/\\\\/g;
-                    $val =~ s/\'/\\\'/g;
-
-                    $key =~ s/[^\]\[0-9a-zA-Z_\+]//g;
-                    $key =~ s/\[{2,}/\[/g;
-                    $key =~ s/\]{2,}/\]/g;
-                    $key =~ s/\\//g;
-                    $key =~ s/\'//g;
-
-                    my @list;
-                    foreach my $n (split /[\[\]]/, $key) {
-                        push @list, $n if length($n) > 0;
-                    }
-
-                    map $array[$index] .= "{'$list[$_]'}", 0 .. $#list;
-
-                    $array[$index] .= " = '$val';";
-                    $index++;
-                }
-
-                my $code = 'my $h = {};';
-                map { $code .= "\$h->$_" } @array;
-                $code .= '$h;';
-
-                my $ret = eval $code;
-
-                if ($@) {
-                    $self->stash(hparams => {});
-                    $self->stash(hparams_error => $@);
-                    return $self->stash('hparams');
-                }
-
-                if (keys %$ret) {
-                    if (@permit) {
-                        foreach my $k (keys %$ret) {
-                            delete $ret->{$k} if grep(/\Q$k/, @permit);
-                        }
-                    }
-
-                    $self->stash(hparams => $ret);
-                }
-            }
-            else {
-                $self->stash(hparams => {});
-            }
-            return $self->stash('hparams');
-        });
-}
-
-1;
-
-__END__
-
-=encoding utf8
-
-=head1 NAME
-
-Mojolicious::Plugin::HashedParams - Transformation request parameters into a hash and multi-hash
-
-=head1 SYNOPSIS
-
-  plugin 'HashedParams';
-
-  # Transmit params:
-  /route?message[body]=PerlOrDie&message[task][id]=32
-    or
-  <input type="text" name="message[task][id]" value="32"> 
-
-  get '/route' => sub {
-    my $self = shift;
-    # you can also use permit parameters
-    $self->hparams( qw(message) );
-    # return all parameters in the hash
-    $self->hparams();
-  };
-
-=head1 AUTHOR
-
-Grishkovelli L<grishkovelli@gmail.com>
-
-=head1 Git
-
-L<https://github.com/grishkovelli/Mojolicious-Plugin-HashedParams>
-
-=head1 COPYRIGHT
-
-Copyright 2013, Grishkovelli.
-
-This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
-
-=cut
diff --git a/t/api/05-machines.t b/t/api/05-machines.t
index db9b39319e5..aca331a6385 100644
--- a/t/api/05-machines.t
+++ b/t/api/05-machines.t
@@ -59,14 +59,14 @@ is_deeply(
 ) || diag explain $t->tx->res->json;
 
 
-$t->post_ok('/api/v1/machines', form => {name => "testmachine"})->status_is(400)
+$t->post_ok('/api/v1/machines', json => {name => "testmachine"})->status_is(400)
   ->json_is('/error', 'Missing parameter: backend');
-$t->post_ok('/api/v1/machines', form => {backend => "kde/usb"})->status_is(400)
+$t->post_ok('/api/v1/machines', json => {backend => "kde/usb"})->status_is(400)
   ->json_is('/error', 'Missing parameter: name');
-$t->post_ok('/api/v1/machines', form => {})->status_is(400)->json_is('/error', 'Missing parameter: backend, name');
+$t->post_ok('/api/v1/machines', json => {})->status_is(400)->json_is('/error', 'Missing parameter: backend, name');
 
 $t->post_ok('/api/v1/machines',
-    form => {name => "testmachine", backend => "qemu", "settings[TEST]" => "val1", "settings[TEST2]" => "val1"})
+    json => {name => "testmachine", backend => "qemu", "settings" => {"TEST" => "val1", "TEST2" => "val1"}})
   ->status_is(200);
 my $machine_id = $t->tx->res->json->{id};
 my $event = OpenQA::Test::Case::find_most_recent_event($t->app->schema, 'table_create');
@@ -80,19 +80,19 @@ $t->get_ok('/api/v1/machines', form => {name => "testmachine"})->status_is(200);
 is($t->tx->res->json->{Machines}->[0]->{id}, $machine_id);
 
 $t->post_ok('/api/v1/machines',
-    form => {name => "testmachineQ", backend => "qemu", "settings[TEST]" => "'v'al1", "settings[TEST2]" => "va'l\'1"})
+    json => {name => "testmachineQ", backend => "qemu", "settings" => {"TEST" => "'v'al1", "TEST2" => "va'l\'1"}})
   ->status_is(200);
 $t->get_ok('/api/v1/machines', form => {name => "testmachineQ"})->status_is(200);
 is($t->tx->res->json->{Machines}->[0]->{settings}->[0]->{value}, "'v'al1");
 is($t->tx->res->json->{Machines}->[0]->{settings}->[1]->{value}, "va'l\'1");
 
-$t->post_ok('/api/v1/machines', form => {name => "testmachineZ", backend => "qemu", "settings[TE'S\'T]" => "'v'al1"})
-  ->status_is(200);
+$t->post_ok('/api/v1/machines',
+    json => {name => "testmachineZ", backend => "qemu", "settings" => {"TE'S\'T" => "'v'al1"}})->status_is(200);
 $t->get_ok('/api/v1/machines', form => {name => "testmachineQ"})->status_is(200);
 is($t->tx->res->json->{Machines}->[0]->{settings}->[0]->{key}, "TEST");
 is($t->tx->res->json->{Machines}->[0]->{settings}->[0]->{value}, "'v'al1");
 
-$t->post_ok('/api/v1/machines', form => {name => "testmachine", backend => "qemu"})->status_is(400);    #already exists
+$t->post_ok('/api/v1/machines', json => {name => "testmachine", backend => "qemu"})->status_is(400);    #already exists
 
 $t->get_ok("/api/v1/machines/$machine_id")->status_is(200);
 is_deeply(
@@ -117,7 +117,7 @@ is_deeply(
 ) || diag explain $t->tx->res->json;
 
 $t->put_ok("/api/v1/machines/$machine_id",
-    form => {name => "testmachine", backend => "qemu", "settings[TEST2]" => "val1"})->status_is(200);
+    json => {name => "testmachine", backend => "qemu", settings => {"TEST2" => "val1"}})->status_is(200);
 
 $t->get_ok("/api/v1/machines/$machine_id")->status_is(200);
 is_deeply(
@@ -143,6 +143,9 @@ $t->put_ok("/api/v1/machines/$machine_id", json => {name => "testmachine", "sett
 $t->put_ok("/api/v1/machines/$machine_id", => {'Content-Type' => 'application/json'} => '{BROKEN JSON')->status_is(400)
   ->json_like('/error', qr/expected, at character offset/);
 
+$t->put_ok("/api/v1/machines/$machine_id", => {'Content-Type' => 'text/html'})->status_is(400)
+  ->json_like('/error', qr/Invalid request Content-Type/);
+
 $t->put_ok("/api/v1/machines/$machine_id",
     json => {name => "testmachine", backend => "qemu", "settings" => {"TEST2" => "val2"}})->status_is(200);
 
@@ -170,12 +173,13 @@ $t->delete_ok("/api/v1/machines/$machine_id")->status_is(404);    #not found
 subtest 'trim whitespace characters' => sub {
     $t->post_ok(
         '/api/v1/machines',
-        form => {
+        json => {
             name => " create_with_space ",
             backend => " qemu ",
-            "settings[ TEST ]" => " test value  ",
-            "settings[TEST2  ]" => " test value2  ",
-        })->status_is(200);
+            settings => {
+                " TEST " => " test value  ",
+                "TEST2  " => " test value2  "
+            }})->status_is(200);
     my $id = $t->tx->res->json->{id};
     $t->get_ok("/api/v1/machines/$id")->status_is(200);
     $t->json_is(
@@ -200,12 +204,13 @@ subtest 'trim whitespace characters' => sub {
 
     $t->put_ok(
         "/api/v1/machines/$id",
-        form => {
+        json => {
             name => "  update_with_space ",
             backend => "qemu ",
-            "settings[ TEST ]" => " new test value  ",
-            "settings[ TEST3]" => "  new test value3 ",
-        })->status_is(200);
+            settings => {
+                " TEST " => " new test value  ",
+                " TEST3" => "  new test value3 "
+            }})->status_is(200);
     $t->get_ok("/api/v1/machines/$id")->status_is(200);
     $t->json_is(
         '' => {
@@ -231,10 +236,10 @@ subtest 'trim whitespace characters' => sub {
 # switch to operator (default client) and try some modifications
 client($t);
 $t->post_ok('/api/v1/machines',
-    form => {name => "testmachine", backend => "qemu", "settings[TEST]" => "val1", "settings[TEST2]" => "val1"})
+    json => {name => "testmachine", backend => "qemu", "settings" => {"TEST" => "val1", "TEST2" => "val1"}})
   ->status_is(403);
 $t->put_ok("/api/v1/machines/$machine_id",
-    form => {name => "testmachine", backend => "qemu", "settings[TEST2]" => "val1"})->status_is(403);
+    json => {name => "testmachine", backend => "qemu", "settings" => {"TEST2" => "val1"}})->status_is(403);
 $t->delete_ok("/api/v1/machines/$machine_id")->status_is(403);
 
 subtest 'server-side limit has precedence over user-specified limit' => sub {