diff --git a/server/json-adapter.cc b/server/json-adapter.cc
index 34c6f75..10ceb31 100644
--- a/server/json-adapter.cc
+++ b/server/json-adapter.cc
@@ -17,6 +17,7 @@
 #include "function_map.hh"
 #include "pep-types.hh"
 #include "json_rpc.hh"
+#include "nulllogger.hh"
 #include "security-token.hh"
 #include "pep-utils.hh"
 
@@ -326,7 +327,7 @@ void OnApiRequest(evhttp_request* req, void* obj)
 	const std::string data_string(data.data(), data.data() + nr );
 	if(nr>0)
 	{
-		std::cout << "\tData: «" << data_string  << "»\n";
+		ja->Log() << "\tData: «" << data_string  << "»\n";
 		bool b = js::read( data_string, p);
 		if(p.type() == js::obj_type)
 		{
@@ -336,14 +337,14 @@ void OnApiRequest(evhttp_request* req, void* obj)
 			answer = make_error( JSON_RPC::PARSE_ERROR, "evbuffer_copyout does not return a JSON string. b=" + std::to_string(b), js::Value{data_string}, 42 );
 		}
 	}else{
-		std::cout << "\tError: " << nr << ".\n";
+		ja->Log() << "\tError: " << nr << ".\n";
 		answer = make_error( JSON_RPC::INTERNAL_ERROR, "evbuffer_copyout returns negative value", p, request_id );
 	}
 	
 	}
 	catch(const std::exception& e)
 	{
-		std::cout << "\tException: \"" << e.what() << "\"\n";
+		std::cerr << "\tException: \"" << e.what() << "\"\n";
 		answer = make_error( JSON_RPC::INTERNAL_ERROR, "Got a std::exception: \"" + std::string(e.what()) + "\"", p, request_id );
 	}
 
@@ -439,19 +440,23 @@ struct JsonAdapter::Internal
 	std::string token;
 	std::map<EventListenerKey, EventListenerValue> eventListener;
 	
+	std::ostream& Log;
 	unsigned    start_port    = 0;
 	unsigned    end_port      = 0;
 	unsigned    port          = 0;
 	unsigned    request_count = 0;
 	evutil_socket_t sock      = -1;
 	bool        running = false;
+	bool        silent  = false;
 	ThreadPool  threads;
-
-    // Sync
-    locked_queue< sync_msg_t * > *sync_queue;
-    PEP_SESSION sync_session;
-    pthread_t sync_thread;
-
+	
+	// Sync
+	locked_queue< sync_msg_t* >* sync_queue = nullptr;
+	PEP_SESSION sync_session;
+	pthread_t sync_thread;
+	
+	Internal(std::ostream& logger) : Log(logger) {}
+	
 	static
 	void requestDone(evhttp_request* req, void* userdata)
 	{
@@ -519,39 +524,40 @@ struct JsonAdapter::Internal
 		
 		return status;
 	}
-
-    int injectSyncMsg(void *msg)
-    {
-        sync_queue->push_back((sync_msg_t *)msg);
-        return 0;
-    }
-
-    void *retrieveNextSyncMsg()
-    {
-        while (!sync_queue->size())
-            // TODO: add blocking dequeue 
-            usleep(100000);
-
-        void *msg = sync_queue->front();
-        sync_queue->pop_front();
-        return msg;
-    }
-
-    void *syncThreadRoutine(void *arg)
-    {
-        PEP_STATUS status = do_sync_protocol(sync_session, arg);
-
-        while (sync_queue->size()) {
-            sync_msg_t *msg = sync_queue->front();
-            sync_queue->pop_front();
-            free_sync_msg(msg);
-        }
-
-        return (void *) status;
-    }
-
+	
+	int injectSyncMsg(void* msg)
+	{
+		sync_queue->push_back((sync_msg_t*)msg);
+		return 0;
+	}
+	
+	void* retrieveNextSyncMsg()
+	{
+		while (!sync_queue->size())
+		// TODO: add blocking dequeue 
+			usleep(100000);
+		
+		void* msg = sync_queue->front();
+		sync_queue->pop_front();
+		return msg;
+	}
+	
+	void* syncThreadRoutine(void* arg)
+	{
+		PEP_STATUS status = do_sync_protocol(sync_session, arg);
+		
+		while (sync_queue->size())
+		{
+			sync_msg_t* msg = sync_queue->front();
+			sync_queue->pop_front();
+			free_sync_msg(msg);
+		}
+		
+		return (void*) status;
+	}
 };
 
+
 PEP_STATUS JsonAdapter::messageToSend(void* obj, message* msg)
 {
 	JsonAdapter* ja = static_cast<JsonAdapter*>(obj);
@@ -565,76 +571,82 @@ PEP_STATUS JsonAdapter::showHandshake(void* obj, pEp_identity* self, pEp_identit
 	return ja->i->showHandshake(self, partner);
 }
 
-int JsonAdapter::injectSyncMsg(void* obj, void *msg)
+
+int JsonAdapter::injectSyncMsg(void* obj, void* msg)
 {
 	JsonAdapter* ja = static_cast<JsonAdapter*>(obj);
 	return ja->i->injectSyncMsg(msg);
 }
 
-void *JsonAdapter::retrieveNextSyncMsg(void* obj)
+
+void* JsonAdapter::retrieveNextSyncMsg(void* obj)
 {
 	JsonAdapter* ja = static_cast<JsonAdapter*>(obj);
 	return ja->i->retrieveNextSyncMsg();
 }
 
-void *JsonAdapter::syncThreadRoutine(void *arg)
+
+void* JsonAdapter::syncThreadRoutine(void* arg)
 {
 	JsonAdapter* ja = static_cast<JsonAdapter*>(arg);
 	return ja->i->syncThreadRoutine(arg);
 }
 
-void JsonAdapter::startSync(void)
+
+void JsonAdapter::startSync()
 {
-    PEP_STATUS status = init(&i->sync_session);
-    if(status != PEP_STATUS_OK || i->sync_session==nullptr)
-    {
-        throw std::runtime_error("Cannot create sync session! status: " + status_to_string(status));
-    }
-
-    i->sync_queue = new locked_queue< sync_msg_t * >();
-
-    status = register_sync_callbacks(i->sync_session,
-                                     (void *) this,
-                                     JsonAdapter::messageToSend,
-                                     JsonAdapter::showHandshake, 
-                                     JsonAdapter::injectSyncMsg,
-                                     JsonAdapter::retrieveNextSyncMsg);
-    if (status != PEP_STATUS_OK)
-        throw std::runtime_error("Cannot register sync callbacks! status: " + status_to_string(status));
-
-    if(pthread_create(&i->sync_thread, NULL, JsonAdapter::syncThreadRoutine, (void *) this) != 0)
-        throw std::runtime_error("Cannot create sync session thread !");
+	PEP_STATUS status = init(&i->sync_session);
+	if(status != PEP_STATUS_OK || i->sync_session==nullptr)
+	{
+		throw std::runtime_error("Cannot create sync session! status: " + status_to_string(status));
+	}
+	
+	i->sync_queue = new locked_queue< sync_msg_t* >();
+	
+	status = register_sync_callbacks(i->sync_session,
+	                                 (void*) this,
+	                                 JsonAdapter::messageToSend,
+	                                 JsonAdapter::showHandshake, 
+	                                 JsonAdapter::injectSyncMsg,
+	                                 JsonAdapter::retrieveNextSyncMsg);
+	if (status != PEP_STATUS_OK)
+		throw std::runtime_error("Cannot register sync callbacks! status: " + status_to_string(status));
+	
+	if(pthread_create(&i->sync_thread, NULL, JsonAdapter::syncThreadRoutine, (void*) this) != 0)
+		throw std::runtime_error("Cannot create sync session thread !");
 }
 
-void JsonAdapter::stopSync(void)
-{  
 
-    i->sync_queue->push_front(NULL);
-    pthread_join(i->sync_thread, NULL);
-
-    unregister_sync_callbacks(i->sync_session);
-
-    delete i->sync_queue;
-
-    release(i->sync_session);
+void JsonAdapter::stopSync()
+{
+	i->sync_queue->push_front(NULL);
+	pthread_join(i->sync_thread, NULL);
+	
+	unregister_sync_callbacks(i->sync_session);
+	delete i->sync_queue;
+	i->sync_queue = nullptr;
+	
+	release(i->sync_session);
 }
 
-JsonAdapter::JsonAdapter(const std::string& address, unsigned start_port, unsigned end_port)
-: i(new Internal)
+
+JsonAdapter::JsonAdapter(const std::string& address, unsigned start_port, unsigned end_port, bool silent)
+: i(new Internal( silent ? nulllogger : std::cerr ))
 {
 	i->eventBase.reset(event_base_new());
 	if (!i->eventBase)
 		throw std::runtime_error("Failed to create new base_event.");
 	
-	i->evHttp.reset( evhttp_new(i->eventBase.get()));
+	i->evHttp.reset( evhttp_new(i->eventBase.get()) );
 	if (!i->evHttp)
 		throw std::runtime_error("Failed to create new evhttp.");
 	
 	i->address    = address;
 	i->start_port = start_port;
 	i->end_port   = end_port;
-
-    startSync();
+	i->silent     = silent;
+	
+	startSync();
 }
 
 
@@ -648,7 +660,7 @@ JsonAdapter::~JsonAdapter()
 void JsonAdapter::run()
 try
 {
-	std::cout << "I have " << session_registry.size() << " registered session(s).\n";
+	Log() << "I have " << session_registry.size() << " registered session(s).\n";
 	
 	std::exception_ptr initExcept;
 	auto ThreadFunc = [&] ()
@@ -656,7 +668,7 @@ try
 		try
 		{
 			const auto id = std::this_thread::get_id();
-			std::cerr << " +++ Thread starts: isRun=" << i->running << ", id=" << id << ". +++\n";
+			Log() << " +++ Thread starts: isRun=" << i->running << ", id=" << id << ". +++\n";
 			const auto q=session_registry.find(id);
 			if(q==session_registry.end())
 			{
@@ -668,14 +680,13 @@ try
 				}
 				
 				session_registry.emplace( id, session);
-				std::cerr << "\tcreated new session for this thread: " << static_cast<void*>(session) << ".\n";
+				Log() << "\tcreated new session for this thread: " << static_cast<void*>(session) << ".\n";
 				
-                status = attach_sync_session(session, i->sync_session);
-                if(status != PEP_STATUS_OK)
-                    throw std::runtime_error("Cannot attach to sync session! status: " + status_to_string(status));
-
+				status = attach_sync_session(session, i->sync_session);
+				if(status != PEP_STATUS_OK)
+					throw std::runtime_error("Cannot attach to sync session! status: " + status_to_string(status));
 			}else{
-				std::cerr << "\tsession for this thread: "  << static_cast<void*>(q->second) << ".\n";
+				Log() << "\tsession for this thread: "  << static_cast<void*>(q->second) << ".\n";
 			}
 			
 			evhttp_set_cb(i->evHttp.get(), ApiRequestUrl.c_str()    , OnApiRequest    , this);
@@ -685,7 +696,7 @@ try
 			if (i->sock == -1) // no port bound, yet
 			{
 				// initialize the pEp engine
-				std::cout << "I have " << session_registry.size() << " registered session(s).\n";
+				Log() << "I have " << session_registry.size() << " registered session(s).\n";
 				
 				unsigned port_ofs = 0;
 try_next_port:
@@ -708,7 +719,7 @@ try_next_port:
 				i->port = i->start_port + port_ofs;
 				i->token = create_security_token(i->address, i->port, BaseUrl);
 				
-				std::cout << "Bound to port " << i->port << ", sec_token=\"" << i->token << "\"\n";
+				Log() << "Bound to port " << i->port << ", sec_token=\"" << i->token << "\"\n";
 			}
 			else
 			{
@@ -719,28 +730,32 @@ try_next_port:
 			unsigned numnum = 1000000;
 			while(i->running)
 			{
-				event_base_loop(i->eventBase.get(), EVLOOP_NONBLOCK);
-				std::this_thread::sleep_for(std::chrono::milliseconds(100));
-				std::cerr << "\r" << ++numnum << ".   ";
+				// once we have libevent 2.1:
+				//event_base_loop(i->eventBase.get(), EVLOOP_NO_EXIT_ON_EMPTY);
+				
+				// for libevent 2.0:
+				event_base_loop(i->eventBase.get(), 0);
+				std::this_thread::sleep_for(std::chrono::milliseconds(333));
+				Log() << "\r" << ++numnum << ".   ";
 			}
 		}
 		catch (const std::exception& e)
 		{
-			std::cerr << " +++ std::exception in ThreadFunc: " << e.what() << "\n";
+			Log() << " +++ std::exception in ThreadFunc: " << e.what() << "\n";
 			initExcept = std::current_exception();
 		}
 		catch (...)
 		{
-			std::cerr << " +++ UNKNOWN EXCEPTION in ThreadFunc +++ ";
+			Log() << " +++ UNKNOWN EXCEPTION in ThreadFunc +++ ";
 			initExcept = std::current_exception();
 		}
-		std::cerr << " +++ Thread exit? isRun=" << i->running << ", id=" << std::this_thread::get_id() << ". +++\n";
+		Log() << " +++ Thread exit? isRun=" << i->running << ", id=" << std::this_thread::get_id() << ". +++\n";
 	};
 	
 	i->running = true;
 	for(int t=0; t<SrvThreadCount; ++t)
 	{
-		std::cout << "Start Thread #" << t << "...\n";
+		Log() << "Start Thread #" << t << "...\n";
 		ThreadPtr thread(new std::thread(ThreadFunc), ThreadDeleter);
 		std::this_thread::sleep_for(std::chrono::milliseconds(500));
 		if (initExcept != std::exception_ptr())
@@ -750,11 +765,12 @@ try_next_port:
 		}
 		i->threads.push_back(std::move(thread));
 	}
-	std::cout << "All " << SrvThreadCount << " thread(s) started.\n";
+	Log() << "All " << SrvThreadCount << " thread(s) started.\n";
 }
 catch (std::exception const &e)
 {
-	std::cerr << "Exception catched in main(): \"" << e.what() << "\"" << std::endl;
+	Log() << "Exception catched in main(): \"" << e.what() << "\"" << std::endl;
+	throw;
 }
 
 
@@ -774,7 +790,7 @@ bool JsonAdapter::verify_security_token(const std::string& s) const
 {
 	if(s!=i->token)
 	{
-		std::cerr << "sec_token=\"" << i->token << "\" (len=" << i->token.size() << ") is unequal to \"" << s << "\" (len=" << s.size() << ")!\n";
+		Log() << "sec_token=\"" << i->token << "\" (len=" << i->token.size() << ") is unequal to \"" << s << "\" (len=" << s.size() << ")!\n";
 	}
 	return s == i->token;
 }
@@ -808,3 +824,9 @@ void JsonAdapter::unregisterEventListener(const std::string& address, unsigned p
 	i->eventListener.erase(q);
 }
 
+
+std::ostream& JsonAdapter::Log() const
+{
+	return i->Log;
+}
+
diff --git a/server/json-adapter.hh b/server/json-adapter.hh
index 2d36c5a..bd1042e 100644
--- a/server/json-adapter.hh
+++ b/server/json-adapter.hh
@@ -9,8 +9,9 @@ class JsonAdapter : public Context
 {
 public:
 	// creates an instance of the JSON adapter. It tries to bind the first available port in the given range
+	// if chatty==true there is some debug output on stderr, if chatty==false the server is silent.
 	// throws std::runtime_error if no port cannot be bound.
-	JsonAdapter(const std::string& address, unsigned start_port, unsigned end_port);
+	JsonAdapter(const std::string& address, unsigned start_port, unsigned end_port, bool chatty);
 	
 	// calls abort() on the instance if it is still running().
 	virtual ~JsonAdapter();
@@ -52,12 +53,15 @@ public:
 
 	static PEP_STATUS messageToSend(void* obj, message* msg);
 	static PEP_STATUS showHandshake(void* obj, pEp_identity* self, pEp_identity* partner);
-    static int injectSyncMsg(void* obj, void *msg);
-    static void *retrieveNextSyncMsg(void* obj);
-    static void *syncThreadRoutine(void *arg);
-
-    void startSync(void);
-    void stopSync(void);
+	static int injectSyncMsg(void* obj, void* msg);
+	static void *retrieveNextSyncMsg(void* obj);
+	static void *syncThreadRoutine(void* arg);
+	
+	void startSync(void);
+	void stopSync(void);
+	
+	// returns the associated log stream (either std::cerr or nulllogger)
+	std::ostream& Log() const;
 
 private:
 	struct Internal;
diff --git a/server/main.cc b/server/main.cc
index 708091f..f95da6e 100644
--- a/server/main.cc
+++ b/server/main.cc
@@ -1,27 +1,69 @@
 #include "json-adapter.hh"
 #include <iostream>
+#include <boost/program_options.hpp>
+namespace po = boost::program_options;
 
-
+bool debug_mode = false;
 std::string address = "127.0.0.1";
 unsigned start_port = 4223;
 unsigned end_port   = 9999;
 
+void print_version()
+{
+	std::cout << "pEp JSON Adapter.\n"
+		"\tversion \"" << JsonAdapter::version() << "\"\n"
+		"\tAPI version " << JsonAdapter::apiVersion() << "\n" 
+		"\tpEpEngine version " << get_engine_version() << "\n"
+		"\n";
+}
+
 int main(int argc, char** argv)
 try
 {
-	JsonAdapter ja( address, start_port, end_port );
+	po::options_description desc("Program options for the JSON Server Adapter");
+	desc.add_options()
+		("help,h", "print this help messages")
+		("version,v", "print program version")
+		("debug,d", po::value<bool>(&debug_mode)->default_value(false), "Run in debug mode, don't fork() in background")
+		("start-port,s", po::value<unsigned>(&start_port)->default_value(start_port),  "First port to bind on")
+		("end-port,e",   po::value<unsigned>(&end_port)->default_value(end_port),      "Last port to bind on")
+		("address,a",    po::value<std::string>(&address)->default_value(address),     "Address to bind on")
+	;
 	
-	ja.run();
+	po::variables_map vm;
+	po::store(po::parse_command_line(argc, argv, desc), vm);
+	po::notify(vm);
 	
-	int input = 0;
-	do{
-		std::cout << "Press <Q> <Enter> to quit." << std::endl;
-		input = std::cin.get();
-		std::cout << "Oh, I got a '" << input << "'. \n";
-	}while(input != 'q' && input != 'Q');
+	if (vm.count("help"))
+	{
+		std::cout << desc << "\n";
+		return 0;
+	}
+	if (vm.count("version"))
+	{
+		print_version();
+		return 0;
+	}
+
+	if( vm.count("debug"))
+	{
+		JsonAdapter ja( address, start_port, end_port, !debug_mode );
+		ja.run();
+		
+		int input = 0;
+		do{
+			std::cout << "Press <Q> <Enter> to quit." << std::endl;
+			input = std::cin.get();
+			std::cout << "Oh, I got a '" << input << "'. \n";
+		}while(input != 'q' && input != 'Q');
+		
+		ja.shutdown(nullptr);
+		std::cout << "Good bye. :-)" << std::endl;
+	}else{
 	
-	ja.shutdown(nullptr);
-	std::cout << "Good bye. :-)" << std::endl;
+		
+	
+	}
 }
 catch (std::exception const &e)
 {