diff --git a/lib/log/GwLog.h b/lib/log/GwLog.h
index ed25841..379ea5e 100644
--- a/lib/log/GwLog.h
+++ b/lib/log/GwLog.h
@@ -16,6 +16,6 @@ class GwLog{
         void logDebug(int level, const char *fmt,...);
         int isActive(int level){return level <= logLevel;};
 };
-#define LOG_DEBUG(level,fmt,...){ if (logger->isActive(level)) logger->logDebug(level,fmt,__VA_ARGS__);}
+#define LOG_DEBUG(level,...){ if (logger->isActive(level)) logger->logDebug(level,__VA_ARGS__);}
 
 #endif
\ No newline at end of file
diff --git a/lib/queue/GwBuffer.h b/lib/queue/GwBuffer.h
new file mode 100644
index 0000000..8e994ca
--- /dev/null
+++ b/lib/queue/GwBuffer.h
@@ -0,0 +1,151 @@
+#ifndef _GWBUFFER_H
+#define _GWBUFFER_H
+#include <string.h>
+#include <stdint.h>
+#include "GwLog.h"
+
+class GwBufferWriter{
+    public:
+        virtual int write(const uint8_t *buffer,size_t len)=0;
+        virtual ~GwBufferWriter(){};
+};
+
+class GwBuffer{
+    public:
+        static const size_t BUFFER_SIZE=1620; // app. 20 NMEA messages
+        typedef enum {
+            OK,
+            ERROR,
+            AGAIN
+        } WriteStatus;
+    private:
+        uint8_t buffer[BUFFER_SIZE];
+        uint8_t *writePointer=buffer;
+        uint8_t *readPointer=buffer;
+        size_t offset(uint8_t* ptr){
+            return (size_t)(ptr-buffer);
+        }
+        GwLog *logger;
+        void lp(const char *fkt,int p=0){
+            LOG_DEBUG(GwLog::DEBUG + 1,"Buffer[%s]: buf=%p,wp=%d,rp=%d,used=%d,free=%d, p=%d",
+                fkt,buffer,offset(writePointer),offset(readPointer),usedSpace(),freeSpace(),p
+            );
+        }
+    public:
+        GwBuffer(GwLog *logger){
+            this->logger=logger;
+        }
+        void reset(){
+            writePointer=buffer;
+            readPointer=buffer;
+            lp("reset");
+        }
+        size_t freeSpace(){
+            if (readPointer < writePointer){
+                size_t rt=BUFFER_SIZE-offset(writePointer)-1+offset(readPointer);
+                return rt;        
+            }
+            if (readPointer == writePointer) return BUFFER_SIZE-1;
+            return readPointer-writePointer-1;
+        }
+        size_t usedSpace(){
+            if (readPointer == writePointer) return 0;
+            if (readPointer < writePointer) return writePointer-readPointer;
+            return BUFFER_SIZE-offset(readPointer)-1+offset(writePointer);
+        }
+        size_t addData(const uint8_t *data,size_t len){
+            lp("addDataE",len);
+            if (len == 0) return 0;
+            if (freeSpace() < len) return 0;
+            size_t written=0;
+            if (writePointer >= readPointer){
+                written=BUFFER_SIZE-offset(writePointer)-1;
+                if (written > len) written=len;
+                if (written) {
+                    memcpy(writePointer,data,written);
+                    len-=written;
+                    data+=written;
+                    writePointer+=written;
+                    if (offset(writePointer) >= (BUFFER_SIZE-1)) writePointer=buffer;
+                }
+                lp("addData1",written);
+                if (len <= 0) {
+                    return written;
+                }
+            }
+            //now we have the write pointer before the read pointer
+            //and we did the length check before - so we can safely copy
+            memcpy(writePointer,data,len);
+            writePointer+=len;
+            lp("addData2",len);
+            return len+written;
+        }
+        /**
+         * write some data to the buffer writer
+         * return an error if the buffer writer returned < 0
+         */
+        WriteStatus fetchData(GwBufferWriter *writer, bool errorIf0 = true)
+        {
+            lp("fetchDataE");
+            size_t len = usedSpace();
+            if (len == 0)
+                return OK;
+            size_t written=0;    
+            size_t plen=len;    
+            if (writePointer < readPointer)
+            {
+                //we need to write from readPointer till end and then till writePointer-1
+                plen = BUFFER_SIZE - offset(readPointer)-1;
+                int rt = writer->write(readPointer, plen);
+                lp("fetchData1",rt);
+                if (rt < 0){
+                    LOG_DEBUG(GwLog::DEBUG+1,"buffer: write returns error %d",rt);
+                    return ERROR;
+                }
+                if (rt > plen){
+                    LOG_DEBUG(GwLog::DEBUG+1,"buffer: write too many bytes(1) %d",rt);
+                    return ERROR;
+                }
+                if (rt == 0){
+                    LOG_DEBUG(GwLog::DEBUG+1,"buffer: write returns 0 (1)");
+                    return (errorIf0 ? ERROR : AGAIN);
+                }
+                readPointer += rt;
+                if (offset(readPointer) >= (BUFFER_SIZE-1))
+                    readPointer = buffer;
+                if (rt < plen)
+                    return AGAIN;
+                if (plen >= len)
+                    return OK;
+                len -=rt; 
+                written+=rt;   
+                //next part - readPointer should be at buffer now
+            }
+            plen=writePointer - readPointer;
+            if (plen == 0) return OK;
+            int rt = writer->write(readPointer, plen);
+            lp("fetchData2",rt);
+            if (rt < 0){
+                LOG_DEBUG(GwLog::DEBUG+1,"buffer: write returns error %d",rt);
+                return ERROR;
+            }
+            if (rt == 0){
+                LOG_DEBUG(GwLog::DEBUG+1,"buffer: write returns 0 (1)");
+                return (errorIf0 ? ERROR : AGAIN);
+            }
+            if (rt > plen){
+                LOG_DEBUG(GwLog::DEBUG+1,"buffer: write too many bytes(2)");
+                return ERROR;
+            }
+            readPointer += rt;
+            if (offset(readPointer) >= (BUFFER_SIZE-1))
+                readPointer = buffer;
+            lp("fetchData3");
+            written+=rt;    
+            if (written < len)
+                return AGAIN;
+            return OK;
+        }
+};
+
+#endif
\ No newline at end of file
diff --git a/lib/socketserver/GwSocketServer.cpp b/lib/socketserver/GwSocketServer.cpp
index 7dacd26..dc59136 100644
--- a/lib/socketserver/GwSocketServer.cpp
+++ b/lib/socketserver/GwSocketServer.cpp
@@ -1,5 +1,95 @@
 #include "GwSocketServer.h"
 #include <ESPmDNS.h>
+#include <lwip/sockets.h>
+#include "GwBuffer.h"
+
+class Writer : public GwBufferWriter{
+    public:
+    wiFiClientPtr client;
+    bool writeError=false;
+    bool timeOut=false;
+    unsigned long writeTimeout;
+    unsigned long lastWrite;
+    bool pending;
+    Writer(wiFiClientPtr client, unsigned long writeTimeout=10000){
+        this->client=client;
+        pending=false;
+        this->writeTimeout=writeTimeout;
+    }
+    virtual ~Writer(){}
+    virtual int write(const uint8_t *buffer,size_t len){
+        int res = send(client->fd(), (void*) buffer, len, MSG_DONTWAIT);
+        if (res < 0){
+            if (errno != EAGAIN){
+                writeError=true;
+                return res;
+            }
+            res=0;
+        }
+        if (res >= len){
+            pending=false;
+        }
+        else{
+            if (!pending){
+                lastWrite=millis();
+                pending=true;
+            }
+            else{
+                //we need to check if we have still not been able 
+                //to write until timeout
+                if (millis() >= (lastWrite+writeTimeout)){
+                    timeOut=true;
+                }
+            }
+        }
+        return res;
+    }
+};
+class GwClient{
+    public:
+        wiFiClientPtr client;
+        GwBuffer *buffer;
+        GwLog *logger;
+        int overflows;
+    private:
+        Writer *writer;
+    public:        
+        GwClient(wiFiClientPtr client,GwLog *logger){
+            this->client=client;
+            this->logger=logger;
+            buffer=new GwBuffer(logger);
+            overflows=0;
+            writer=new Writer(client);
+        }
+        ~GwClient(){
+            delete writer;
+        }
+        bool enqueue(uint8_t *data, size_t len){
+            if (len == 0) return true;
+            size_t rt=buffer->addData(data,len);
+            if (rt < len){
+                LOG_DEBUG(GwLog::LOG,"overflow on %s",client->remoteIP().toString().c_str());
+                overflows++;
+                return false;
+            }
+            return true;
+        }
+        bool hasData(){
+            return buffer->usedSpace() > 0;
+        }
+        GwBuffer::WriteStatus write(){
+            GwBuffer::WriteStatus rt=buffer->fetchData(writer,false);
+            if (rt != GwBuffer::OK){
+                LOG_DEBUG(GwLog::DEBUG+1,"write returns %d on %s",rt,client->remoteIP().toString().c_str());
+            }
+            if (writer->timeOut ){
+                LOG_DEBUG(GwLog::LOG,"timeout on %s",client->remoteIP().toString().c_str());
+                return GwBuffer::ERROR;
+            }    
+            return rt;
+        }
+};
+
 
 GwSocketServer::GwSocketServer(const GwConfigHandler *config,GwLog *logger){
     this->config=config;
@@ -20,23 +110,33 @@ void GwSocketServer::loop()
     if (client){
         logger->logString("new client connected from %s",
             client.remoteIP().toString().c_str());
-        clients.push_back(wiFiClientPtr(new WiFiClient(client)));
+        fcntl(client.fd(), F_SETFL, O_NONBLOCK);
+        gwClientPtr newClient(new GwClient(wiFiClientPtr(new WiFiClient(client)),logger));    
+        clients.push_back(newClient);
+    }
+    //sending
+    for (auto it = clients.begin(); it != clients.end();it++){
+        GwBuffer::WriteStatus rt=(*it)->write();
+        if (rt == GwBuffer::ERROR){
+            LOG_DEBUG(GwLog::ERROR,"write error on %s, closing",(*it)->client->remoteIP().toString().c_str());
+            (*it)->client->stop();
+        }
     }
     for (auto it = clients.begin(); it != clients.end();it++)
     {
         if ((*it) != NULL)
         {
-            if (!(*it)->connected())
+            if (!(*it)->client->connected())
             {
-                logger->logString("client disconnect ");
-                (*it)->stop();
+                logger->logString("client disconnect");
+                (*it)->client->stop();
                 clients.erase(it);
             }
             else
             {
-                while ((*it)->available())
+                while ((*it)->client->available())
                 {
-                    char c = (*it)->read();
+                    char c = (*it)->client->read();
                     //TODO: read data
                 }
             }
@@ -48,9 +148,20 @@ void GwSocketServer::loop()
     }
 }
 void GwSocketServer::sendToClients(const char *buf){
+    int len=strlen(buf);
+    char buffer[len+2];
+    memcpy(buffer,buf,len);
+    buffer[len]=0x0d;
+    len++;
+    buffer[len]=0x0a;
+    len++;
     for (auto it = clients.begin() ; it != clients.end(); it++) {
-    if ( (*it) != NULL && (*it)->connected() ) {
-      (*it)->println(buf);
+    if ( (*it) != NULL && (*it)->client->connected() ) {
+        bool rt=(*it)->enqueue((uint8_t*)buffer,len);
+        if (!rt){
+            LOG_DEBUG(GwLog::DEBUG,"overflow in send to %s",(*it)->client->remoteIP().toString().c_str());    
+        }
+        
     }
   }
 }
diff --git a/lib/socketserver/GwSocketServer.h b/lib/socketserver/GwSocketServer.h
index 9ad946b..2b758f2 100644
--- a/lib/socketserver/GwSocketServer.h
+++ b/lib/socketserver/GwSocketServer.h
@@ -7,11 +7,13 @@
 #include <WiFi.h>
 
 using wiFiClientPtr = std::shared_ptr<WiFiClient>;
+class GwClient;
+using gwClientPtr = std::shared_ptr<GwClient>;
 class GwSocketServer{
     private:
         const GwConfigHandler *config;
         GwLog *logger;
-        std::list<wiFiClientPtr> clients;
+        std::list<gwClientPtr> clients;
         WiFiServer *server=NULL;
     public:
         GwSocketServer(const GwConfigHandler *config,GwLog *logger);