diff --git a/lib/App/EvalServerAdvanced.pm b/lib/App/EvalServerAdvanced.pm
index c2e61cc..b1fb2fe 100644
--- a/lib/App/EvalServerAdvanced.pm
+++ b/lib/App/EvalServerAdvanced.pm
@@ -80,15 +80,15 @@ method init() {
             if ($res) {
               $$buffref = $newbuf;
 
-              if ($message->isa("App::EvalServerAdvanced::Protocol::Eval")) {
+              if ($message->isa('App::EvalServerAdvanced::Protocol::Evalserver::Eval')) {
                 my $sequence = $message->sequence;
-                my $out_encoding = eval {$message->encoding} // "utf8";
+                my $out_encoding = eval {$message->encoding} // 'utf8';
                 try {
-                  my $prio = ($message->prio->has_pr_deadline ? "deadline" :
-                             ($message->prio->has_pr_batch    ? "batch" : "realtime"));
+                  my $prio = (defined $message->prio->pr_deadline ? 'deadline' :
+                             ($message->prio->pr_batch            ? 'batch'    : 'realtime'));
 
                   my $evalobj = {
-                    files => $message->{files},
+                    files => $message->files,
                     priority => $prio,
                     language => $message->language,
                   };
@@ -96,7 +96,7 @@ method init() {
                   debug Dumper($evalobj);
 
                   if ($prio eq 'deadline') {
-                    $evalobj->{priority_deadline} = $message->prio->pr_deadline->milliseconds;
+                    $evalobj->{priority_deadline} = $message->prio->pr_deadline;
                   };
 
                   my $job = $es_self->jobman->add_job($evalobj);
diff --git a/lib/App/EvalServerAdvanced/Protocol.pm b/lib/App/EvalServerAdvanced/Protocol.pm
new file mode 100644
index 0000000..77da6b2
--- /dev/null
+++ b/lib/App/EvalServerAdvanced/Protocol.pm
@@ -0,0 +1,54 @@
+package App::EvalServerAdvanced::Protocol;
+
+use strict;
+use warnings;
+use Google::ProtocolBuffers::Dynamic;
+
+use Exporter 'import';
+our @EXPORT = qw(decode_message encode_message);
+
+use File::ShareDir ();
+use File::Spec;
+use File::Basename qw(dirname);
+
+our $dynamic = Google::ProtocolBuffers::Dynamic->new;
+my $proto_file;
+eval {
+    $proto_file = File::ShareDir::dist_file('App-EvalServerAdvanced', 'proto/evalserver.proto');
+};
+if (!$proto_file || !-f $proto_file) {
+    $proto_file = File::Spec->rel2abs(File::Spec->catfile(
+        dirname(__FILE__), '..', '..', '..', 'share', 'proto', 'evalserver.proto'
+    ));
+}
+$dynamic->load_file($proto_file);
+$dynamic->map_package('App.EvalServerAdvanced.Protocol', 'App::EvalServerAdvanced::Protocol');
+
+sub decode_message {
+    my ($data_ref) = @_;
+    return (0, undef, $$data_ref) unless length($$data_ref) >= 4;
+
+    my $len = unpack('N', substr($$data_ref, 0, 4));
+    return (0, undef, $$data_ref) if length($$data_ref) < 4 + $len;
+
+    my $payload = substr($$data_ref, 4, $len);
+    my $newbuf  = substr($$data_ref, 4 + $len);
+
+    my $packet = $dynamic->decode('App.EvalServerAdvanced.Protocol.Packet', $payload);
+    my $inner_msg = $packet->eval // $packet->response // $packet->warning;
+
+    return (1, $inner_msg, $newbuf);
+}
+
+sub encode_message {
+    my ($type, $args) = @_;
+
+    my $packet_data = {
+        $type => $args
+    };
+
+    my $bytes = $dynamic->encode('App.EvalServerAdvanced.Protocol.Packet', $packet_data);
+    return pack('N', length($bytes)) . $bytes;
+}
+
+1;
diff --git a/share/proto/evalserver.proto b/share/proto/evalserver.proto
new file mode 100644
index 0000000..e576861
--- /dev/null
+++ b/share/proto/evalserver.proto
@@ -0,0 +1,40 @@
+syntax = "proto2";
+
+package App.EvalServerAdvanced.Protocol;
+
+message Priority {
+  optional uint64 pr_deadline = 1;
+  optional bool pr_batch = 2;
+  optional bool pr_realtime = 3;
+}
+
+message File {
+  optional string name = 1;
+  optional bytes content = 2;
+}
+
+message Eval {
+  optional uint64 sequence = 1;
+  optional string language = 2;
+  optional string encoding = 3;
+  optional Priority prio = 4;
+  repeated File files = 5;
+}
+
+message Response {
+  optional uint64 sequence = 1;
+  optional string contents = 2;
+  optional string encoding = 3;
+}
+
+message Warning {
+  optional uint64 sequence = 1;
+  optional string message = 2;
+  optional string encoding = 3;
+}
+
+message Packet {
+  optional Eval eval = 1;
+  optional Response response = 2;
+  optional Warning warning = 3;
+}