diff --git a/src/core/httprequest.h b/src/core/httprequest.h
index 4d2920c0..9111a8c2 100644
--- a/src/core/httprequest.h
+++ b/src/core/httprequest.h
@@ -24,6 +24,8 @@
 #ifndef HTTPREQUEST_H
 #define HTTPREQUEST_H
 
+#include "cowbytearray.h"
+#include "cowstring.h"
 #include "cowurl.h"
 #include "httpheaders.h"
 #include <QHostAddress>
@@ -51,19 +53,20 @@ class HttpRequest {
 
     virtual QHostAddress peerAddress() const = 0;
 
-    virtual void setConnectHost(const QString &host) = 0;
+    virtual void setConnectHost(const CowString &host) = 0;
     virtual void setConnectPort(int port) = 0;
     virtual void setIgnorePolicies(bool on) = 0;
     virtual void setTrustConnectHost(bool on) = 0;
     virtual void setIgnoreTlsErrors(bool on) = 0;
     virtual void setTimeout(int msecs) = 0;
-    virtual void setClientCert(const QString &cert, const QString &key) = 0;
+    virtual void setClientCert(const CowString &cert, const CowString &key) = 0;
 
-    virtual void start(const QString &method, const CowUrl &uri, const HttpHeaders &headers) = 0;
-    virtual void beginResponse(int code, const QByteArray &reason, const HttpHeaders &headers) = 0;
+    virtual void start(const CowString &method, const CowUrl &uri, const HttpHeaders &headers) = 0;
+    virtual void beginResponse(int code, const CowByteArray &reason,
+                               const HttpHeaders &headers) = 0;
 
     // May call this multiple times
-    virtual void writeBody(const QByteArray &body) = 0;
+    virtual void writeBody(const CowByteArray &body) = 0;
 
     virtual void endBody() = 0;
 
@@ -75,15 +78,15 @@ class HttpRequest {
     virtual bool isErrored() const = 0;
     virtual ErrorCondition errorCondition() const = 0;
 
-    virtual QString requestMethod() const = 0;
+    virtual CowString requestMethod() const = 0;
     virtual CowUrl requestUri() const = 0;
     virtual HttpHeaders requestHeaders() const = 0;
 
     virtual int responseCode() const = 0;
-    virtual QByteArray responseReason() const = 0;
+    virtual CowByteArray responseReason() const = 0;
     virtual HttpHeaders responseHeaders() const = 0;
 
-    virtual QByteArray readBody(int size = -1) = 0; // Takes from the buffer
+    virtual CowByteArray readBody(int size = -1) = 0; // Takes from the buffer
 
     // Indicates input data and/or input finished
     Signal readyRead;
diff --git a/src/core/zhttprequest.cpp b/src/core/zhttprequest.cpp
index 85c6a9c1..dbe3bf17 100644
--- a/src/core/zhttprequest.cpp
+++ b/src/core/zhttprequest.cpp
@@ -66,17 +66,17 @@ class ZhttpRequest::Private {
     bool doReq;
     QByteArray toAddress;
     QHostAddress peerAddress;
-    QString connectHost;
+    CowString connectHost;
     int connectPort;
     bool ignorePolicies;
     bool trustConnectHost;
     bool ignoreTlsErrors;
     int timeout;
-    QString clientCert;
-    QString clientKey;
+    CowString clientCert;
+    CowString clientKey;
     bool sendBodyAfterAck;
     Variant passthrough;
-    QString requestMethod;
+    CowString requestMethod;
     CowUrl requestUri;
     HttpHeaders requestHeaders;
     BufferList requestBodyBuf;
@@ -88,7 +88,7 @@ class ZhttpRequest::Private {
     bool haveRequestBody;
     bool haveResponseValues;
     int responseCode;
-    QByteArray responseReason;
+    CowByteArray responseReason;
     HttpHeaders responseHeaders;
     BufferList responseBodyBuf;
     Variant userData;
@@ -202,10 +202,10 @@ class ZhttpRequest::Private {
         if (packet.credits != -1)
             outCredits = packet.credits;
 
-        requestMethod = packet.method.asQString();
+        requestMethod = packet.method;
         requestUri = packet.uri;
         requestHeaders = packet.headers;
-        requestBodyBuf += packet.body.asQByteArray();
+        requestBodyBuf += packet.body;
 
         passthrough = packet.passthrough;
 
@@ -342,7 +342,7 @@ class ZhttpRequest::Private {
         }
     }
 
-    QByteArray readBody(int size) {
+    CowByteArray readBody(int size) {
         if (server) {
             QByteArray out = requestBodyBuf.take(size).asQByteArray();
             if (out.isEmpty())
@@ -526,7 +526,7 @@ class ZhttpRequest::Private {
         refreshTimeout();
 
         if (packet.type == ZhttpRequestPacket::Data) {
-            requestBodyBuf += packet.body.asQByteArray();
+            requestBodyBuf += packet.body;
 
             bool done = haveRequestBody;
 
@@ -664,7 +664,7 @@ class ZhttpRequest::Private {
                 haveResponseValues = true;
 
                 responseCode = packet.code;
-                responseReason = packet.reason.asQByteArray();
+                responseReason = packet.reason;
                 responseHeaders = packet.headers;
 
                 needToSendHeaders = true;
@@ -678,7 +678,7 @@ class ZhttpRequest::Private {
                     log_warning("zhttp client: id=%s server is sending too fast", id.data());
             }
 
-            responseBodyBuf += packet.body.asQByteArray();
+            responseBodyBuf += packet.body;
 
             if (packet.more) {
                 if (!doReq && packet.credits > 0) {
@@ -711,7 +711,7 @@ class ZhttpRequest::Private {
         }
     }
 
-    void writeBody(const QByteArray &body) {
+    void writeBody(const CowByteArray &body) {
         assert(!bodyFinished);
         assert(!pausing && !paused);
 
@@ -1051,7 +1051,7 @@ Variant ZhttpRequest::passthroughData() const { return d->passthrough; }
 
 QHostAddress ZhttpRequest::peerAddress() const { return d->peerAddress; }
 
-void ZhttpRequest::setConnectHost(const QString &host) { d->connectHost = host; }
+void ZhttpRequest::setConnectHost(const CowString &host) { d->connectHost = host; }
 
 void ZhttpRequest::setConnectPort(int port) { d->connectPort = port; }
 
@@ -1063,7 +1063,7 @@ void ZhttpRequest::setIgnoreTlsErrors(bool on) { d->ignoreTlsErrors = on; }
 
 void ZhttpRequest::setTimeout(int msecs) { d->timeout = msecs; }
 
-void ZhttpRequest::setClientCert(const QString &cert, const QString &key) {
+void ZhttpRequest::setClientCert(const CowString &cert, const CowString &key) {
     d->clientCert = cert;
     d->clientKey = key;
 }
@@ -1076,7 +1076,7 @@ void ZhttpRequest::setPassthroughData(const Variant &data) { d->passthrough = da
 
 void ZhttpRequest::setQuiet(bool on) { d->quiet = on; }
 
-void ZhttpRequest::start(const QString &method, const CowUrl &uri, const HttpHeaders &headers) {
+void ZhttpRequest::start(const CowString &method, const CowUrl &uri, const HttpHeaders &headers) {
     assert(!d->server);
 
     d->requestMethod = method;
@@ -1085,7 +1085,7 @@ void ZhttpRequest::start(const QString &method, const CowUrl &uri, const HttpHea
     d->startClient();
 }
 
-void ZhttpRequest::beginResponse(int code, const QByteArray &reason, const HttpHeaders &headers) {
+void ZhttpRequest::beginResponse(int code, const CowByteArray &reason, const HttpHeaders &headers) {
     assert(d->server);
     assert(d->state == Private::ServerReceiving || d->state == Private::ServerResponseWait);
 
@@ -1095,7 +1095,7 @@ void ZhttpRequest::beginResponse(int code, const QByteArray &reason, const HttpH
     d->beginResponse();
 }
 
-void ZhttpRequest::writeBody(const QByteArray &body) { d->writeBody(body); }
+void ZhttpRequest::writeBody(const CowByteArray &body) { d->writeBody(body); }
 
 void ZhttpRequest::endBody() { d->endBody(); }
 
@@ -1164,7 +1164,7 @@ bool ZhttpRequest::isErrored() const { return d->errored; }
 
 HttpRequest::ErrorCondition ZhttpRequest::errorCondition() const { return d->errorCondition; }
 
-QString ZhttpRequest::requestMethod() const { return d->requestMethod; }
+CowString ZhttpRequest::requestMethod() const { return d->requestMethod; }
 
 CowUrl ZhttpRequest::requestUri() const { return d->requestUri; }
 
@@ -1172,11 +1172,11 @@ HttpHeaders ZhttpRequest::requestHeaders() const { return d->requestHeaders; }
 
 int ZhttpRequest::responseCode() const { return d->responseCode; }
 
-QByteArray ZhttpRequest::responseReason() const { return d->responseReason; }
+CowByteArray ZhttpRequest::responseReason() const { return d->responseReason; }
 
 HttpHeaders ZhttpRequest::responseHeaders() const { return d->responseHeaders; }
 
-QByteArray ZhttpRequest::readBody(int size) { return d->readBody(size); }
+CowByteArray ZhttpRequest::readBody(int size) { return d->readBody(size); }
 
 void ZhttpRequest::setupClient(ZhttpManager *manager, bool req) {
     d->manager = manager;
diff --git a/src/core/zhttprequest.h b/src/core/zhttprequest.h
index eccd2320..85bea17e 100644
--- a/src/core/zhttprequest.h
+++ b/src/core/zhttprequest.h
@@ -24,6 +24,8 @@
 #ifndef ZHTTPREQUEST_H
 #define ZHTTPREQUEST_H
 
+#include "cowbytearray.h"
+#include "cowstring.h"
 #include "cowurl.h"
 #include "httprequest.h"
 #include "variant.h"
@@ -46,10 +48,10 @@ class ZhttpRequest : public HttpRequest {
     public:
         Rid rid;
         QHostAddress peerAddress;
-        QString requestMethod;
+        CowString requestMethod;
         CowUrl requestUri;
         HttpHeaders requestHeaders;
-        QByteArray requestBody;
+        CowByteArray requestBody;
         int responseCode;
         int inSeq;
         int outSeq;
@@ -79,18 +81,18 @@ class ZhttpRequest : public HttpRequest {
 
     virtual QHostAddress peerAddress() const;
 
-    virtual void setConnectHost(const QString &host);
+    virtual void setConnectHost(const CowString &host);
     virtual void setConnectPort(int port);
     virtual void setIgnorePolicies(bool on);
     virtual void setTrustConnectHost(bool on);
     virtual void setIgnoreTlsErrors(bool on);
     virtual void setTimeout(int msecs);
-    virtual void setClientCert(const QString &cert, const QString &key);
+    virtual void setClientCert(const CowString &cert, const CowString &key);
 
-    virtual void start(const QString &method, const CowUrl &uri, const HttpHeaders &headers);
-    virtual void beginResponse(int code, const QByteArray &reason, const HttpHeaders &headers);
+    virtual void start(const CowString &method, const CowUrl &uri, const HttpHeaders &headers);
+    virtual void beginResponse(int code, const CowByteArray &reason, const HttpHeaders &headers);
 
-    virtual void writeBody(const QByteArray &body);
+    virtual void writeBody(const CowByteArray &body);
 
     virtual void endBody();
 
@@ -102,15 +104,15 @@ class ZhttpRequest : public HttpRequest {
     virtual bool isErrored() const;
     virtual ErrorCondition errorCondition() const;
 
-    virtual QString requestMethod() const;
+    virtual CowString requestMethod() const;
     virtual CowUrl requestUri() const;
     virtual HttpHeaders requestHeaders() const;
 
     virtual int responseCode() const;
-    virtual QByteArray responseReason() const;
+    virtual CowByteArray responseReason() const;
     virtual HttpHeaders responseHeaders() const;
 
-    virtual QByteArray readBody(int size = -1);
+    virtual CowByteArray readBody(int size = -1);
 
 private:
     class Private;
diff --git a/src/handler/filter.cpp b/src/handler/filter.cpp
index e4b076b3..1a371f2e 100644
--- a/src/handler/filter.cpp
+++ b/src/handler/filter.cpp
@@ -341,7 +341,7 @@ class HttpFilterInner {
             }
         }
 
-        QByteArray body = req->readBody();
+        QByteArray body = req->readBody().asQByteArray();
 
         if (mode == HttpFilter::Modify) {
             if (responseSizeMax >= 0 && responseBody.size() + body.size() > responseSizeMax) {
diff --git a/src/handler/filtertest.cpp b/src/handler/filtertest.cpp
index c1bdf404..36308050 100644
--- a/src/handler/filtertest.cpp
+++ b/src/handler/filtertest.cpp
@@ -105,7 +105,7 @@ class HttpFilterServer {
         }
 
         CowUrl uri = req->requestUri();
-        QByteArray body = req->readBody();
+        QByteArray body = req->readBody().asQByteArray();
         bool preferInternal = req->passthroughData().toMap().value("prefer-internal").toBool();
 
         if (uri.path() == "/filter/accept") {
diff --git a/src/handler/httpsession.cpp b/src/handler/httpsession.cpp
index ca27fd2f..778d3a31 100644
--- a/src/handler/httpsession.cpp
+++ b/src/handler/httpsession.cpp
@@ -1086,7 +1086,7 @@ class HttpSession::Private {
                     if (avail <= 0)
                         return;
 
-                    QByteArray buf = outReq->readBody(avail);
+                    QByteArray buf = outReq->readBody(avail).asQByteArray();
 
                     if (responseFilters) {
                         buf = responseFilters->update(buf);
@@ -1197,8 +1197,8 @@ class HttpSession::Private {
         }
     }
 
-    void logRequest(const QString &method, const CowUrl &uri, const HttpHeaders &headers, int code,
-                    int bodySize) {
+    void logRequest(const CowString &method, const CowUrl &uri, const HttpHeaders &headers,
+                    int code, int bodySize) {
         LogUtil::RequestData rd;
 
         // Only log route id if explicitly set
@@ -1218,7 +1218,7 @@ class HttpSession::Private {
         LogUtil::logRequest(LOG_LEVEL_INFO, rd, logConfig);
     }
 
-    void logRequestError(const QString &method, const CowUrl &uri, const HttpHeaders &headers) {
+    void logRequestError(const CowString &method, const CowUrl &uri, const HttpHeaders &headers) {
         LogUtil::RequestData rd;
 
         // Only log route id if explicitly set
diff --git a/src/proxy/proxysession.cpp b/src/proxy/proxysession.cpp
index 05631633..9a039c66 100644
--- a/src/proxy/proxysession.cpp
+++ b/src/proxy/proxysession.cpp
@@ -485,7 +485,7 @@ class ProxySession::Private {
         if (maxBytes == 0)
             return;
 
-        QByteArray buf = inRequest->request()->readBody(maxBytes);
+        QByteArray buf = inRequest->request()->readBody(maxBytes).asQByteArray();
         if (!buf.isEmpty()) {
             log_debug("proxysession: %p input chunk: %d", q, buf.size());
 
@@ -792,7 +792,7 @@ class ProxySession::Private {
         QByteArray buf;
         int maxBytes = (buffering ? MAX_INITIAL_BUFFER - responseBody.size() : MAX_STREAM_BUFFER);
         if (maxBytes > 0)
-            buf = zhttpRequest->readBody(maxBytes);
+            buf = zhttpRequest->readBody(maxBytes).asQByteArray();
 
         if (!buf.isEmpty()) {
             incCounter(Stats::ServerContentBytesReceived, buf.size());
@@ -960,7 +960,7 @@ class ProxySession::Private {
             responseData.reason = zhttpRequest->responseReason();
             responseData.headers = zhttpRequest->responseHeaders();
 
-            QByteArray buf = zhttpRequest->readBody(MAX_INITIAL_BUFFER);
+            QByteArray buf = zhttpRequest->readBody(MAX_INITIAL_BUFFER).asQByteArray();
 
             incCounter(Stats::ServerHeaderBytesReceived,
                        ZhttpManager::estimateResponseHeaderBytes(responseData.code,
diff --git a/src/proxy/requestsession.cpp b/src/proxy/requestsession.cpp
index e738bd3d..24f2aeb4 100644
--- a/src/proxy/requestsession.cpp
+++ b/src/proxy/requestsession.cpp
@@ -457,7 +457,7 @@ class RequestSession::Private {
                 q->inspected(idata);
             }
         } else if (state == ReceivingForAccept) {
-            QByteArray buf = zhttpRequest->readBody();
+            QByteArray buf = zhttpRequest->readBody().asQByteArray();
             if (in.size() + buf.size() > MAX_ACCEPT_REQUEST_BODY) {
                 respondError(413, "Request Entity Too Large",
                              QString("Body must not exceed %1 bytes").arg(MAX_ACCEPT_REQUEST_BODY));
diff --git a/src/proxy/sockjsmanager.cpp b/src/proxy/sockjsmanager.cpp
index e51ac6a9..987090c0 100644
--- a/src/proxy/sockjsmanager.cpp
+++ b/src/proxy/sockjsmanager.cpp
@@ -371,7 +371,7 @@ class SockJsManager::Private {
     }
 
     void handleRequest(Session *s) {
-        QString method = s->req->requestMethod();
+        CowString method = s->req->requestMethod();
         log_debug("sockjs request: path=[%s], asUri=[%s]", s->path.data(),
                   s->asUri.toEncoded().data());
 
diff --git a/src/proxy/testhttprequest.cpp b/src/proxy/testhttprequest.cpp
index 531ca35d..7fc83d73 100644
--- a/src/proxy/testhttprequest.cpp
+++ b/src/proxy/testhttprequest.cpp
@@ -126,7 +126,7 @@ QHostAddress TestHttpRequest::peerAddress() const {
     return QHostAddress();
 }
 
-void TestHttpRequest::setConnectHost([[maybe_unused]] const QString &host) {}
+void TestHttpRequest::setConnectHost([[maybe_unused]] const CowString &host) {}
 
 void TestHttpRequest::setConnectPort([[maybe_unused]] int port) {}
 
@@ -138,10 +138,11 @@ void TestHttpRequest::setIgnoreTlsErrors([[maybe_unused]] bool on) {}
 
 void TestHttpRequest::setTimeout([[maybe_unused]] int msecs) {}
 
-void TestHttpRequest::setClientCert([[maybe_unused]] const QString &cert,
-                                    [[maybe_unused]] const QString &key) {}
+void TestHttpRequest::setClientCert([[maybe_unused]] const CowString &cert,
+                                    [[maybe_unused]] const CowString &key) {}
 
-void TestHttpRequest::start(const QString &method, const CowUrl &uri, const HttpHeaders &headers) {
+void TestHttpRequest::start(const CowString &method, const CowUrl &uri,
+                            const HttpHeaders &headers) {
     assert(d->state == Private::Idle);
 
     d->state = Private::ReceivingRequest;
@@ -152,13 +153,13 @@ void TestHttpRequest::start(const QString &method, const CowUrl &uri, const Http
 }
 
 void TestHttpRequest::beginResponse([[maybe_unused]] int code,
-                                    [[maybe_unused]] const QByteArray &reason,
+                                    [[maybe_unused]] const CowByteArray &reason,
                                     [[maybe_unused]] const HttpHeaders &headers) {
     // This class is client only
     assert(0);
 }
 
-void TestHttpRequest::writeBody(const QByteArray &body) {
+void TestHttpRequest::writeBody(const CowByteArray &body) {
     if (d->state == Private::ReceivingRequest) {
         if (d->requestBody.size() + body.size() > MAX_REQUEST_SIZE) {
             d->state = Private::Responding;
@@ -166,7 +167,7 @@ void TestHttpRequest::writeBody(const QByteArray &body) {
             return;
         }
 
-        QByteArray buf = body.mid(0, MAX_REQUEST_SIZE - d->requestBody.size());
+        CowByteArray buf = body.mid(0, MAX_REQUEST_SIZE - d->requestBody.size());
 
         if (!buf.isEmpty()) {
             d->requestBody += buf;
@@ -205,7 +206,7 @@ bool TestHttpRequest::isErrored() const {
 
 HttpRequest::ErrorCondition TestHttpRequest::errorCondition() const { return d->errorCondition; }
 
-QString TestHttpRequest::requestMethod() const { return d->request.method.asQString(); }
+CowString TestHttpRequest::requestMethod() const { return d->request.method; }
 
 CowUrl TestHttpRequest::requestUri() const { return d->request.uri; }
 
@@ -213,8 +214,8 @@ HttpHeaders TestHttpRequest::requestHeaders() const { return d->request.headers;
 
 int TestHttpRequest::responseCode() const { return d->response.code; }
 
-QByteArray TestHttpRequest::responseReason() const { return d->response.reason.asQByteArray(); }
+CowByteArray TestHttpRequest::responseReason() const { return d->response.reason; }
 
 HttpHeaders TestHttpRequest::responseHeaders() const { return d->response.headers; }
 
-QByteArray TestHttpRequest::readBody(int size) { return d->responseBody.take(size).asQByteArray(); }
+CowByteArray TestHttpRequest::readBody(int size) { return d->responseBody.take(size); }
diff --git a/src/proxy/testhttprequest.h b/src/proxy/testhttprequest.h
index ec7b2531..7d04019e 100644
--- a/src/proxy/testhttprequest.h
+++ b/src/proxy/testhttprequest.h
@@ -23,6 +23,8 @@
 #ifndef TESTHTTPREQUEST_H
 #define TESTHTTPREQUEST_H
 
+#include "cowbytearray.h"
+#include "cowstring.h"
 #include "cowurl.h"
 #include "httprequest.h"
 
@@ -39,18 +41,18 @@ class TestHttpRequest : public HttpRequest {
 
     virtual QHostAddress peerAddress() const;
 
-    virtual void setConnectHost(const QString &host);
+    virtual void setConnectHost(const CowString &host);
     virtual void setConnectPort(int port);
     virtual void setIgnorePolicies(bool on);
     virtual void setTrustConnectHost(bool on);
     virtual void setIgnoreTlsErrors(bool on);
     virtual void setTimeout(int msecs);
-    virtual void setClientCert(const QString &cert, const QString &key);
+    virtual void setClientCert(const CowString &cert, const CowString &key);
 
-    virtual void start(const QString &method, const CowUrl &uri, const HttpHeaders &headers);
-    virtual void beginResponse(int code, const QByteArray &reason, const HttpHeaders &headers);
+    virtual void start(const CowString &method, const CowUrl &uri, const HttpHeaders &headers);
+    virtual void beginResponse(int code, const CowByteArray &reason, const HttpHeaders &headers);
 
-    virtual void writeBody(const QByteArray &body);
+    virtual void writeBody(const CowByteArray &body);
 
     virtual void endBody();
 
@@ -62,15 +64,15 @@ class TestHttpRequest : public HttpRequest {
     virtual bool isErrored() const;
     virtual ErrorCondition errorCondition() const;
 
-    virtual QString requestMethod() const;
+    virtual CowString requestMethod() const;
     virtual CowUrl requestUri() const;
     virtual HttpHeaders requestHeaders() const;
 
     virtual int responseCode() const;
-    virtual QByteArray responseReason() const;
+    virtual CowByteArray responseReason() const;
     virtual HttpHeaders responseHeaders() const;
 
-    virtual QByteArray readBody(int size = -1);
+    virtual CowByteArray readBody(int size = -1);
 
 private:
     class Private;
diff --git a/src/proxy/websocketoverhttp.cpp b/src/proxy/websocketoverhttp.cpp
index f59a3ff2..b10a5d56 100644
--- a/src/proxy/websocketoverhttp.cpp
+++ b/src/proxy/websocketoverhttp.cpp
@@ -549,7 +549,7 @@ class WebSocketOverHttp::Private {
         retries = 0;
 
         int responseCode = req->responseCode();
-        QByteArray responseReason = req->responseReason();
+        CowByteArray responseReason = req->responseReason();
         HttpHeaders responseHeaders = req->responseHeaders();
         QByteArray responseBody = inBuf.take().asQByteArray();
 
diff --git a/src/proxy/websocketoverhttptest.cpp b/src/proxy/websocketoverhttptest.cpp
index 9a5f2c61..a54cf39c 100644
--- a/src/proxy/websocketoverhttptest.cpp
+++ b/src/proxy/websocketoverhttptest.cpp
@@ -105,7 +105,7 @@ class WohServer {
 
         CowUrl uri = req->requestUri();
         HttpHeaders headers = req->requestHeaders();
-        QByteArray body = req->readBody();
+        QByteArray body = req->readBody().asQByteArray();
 
         if (headers.get("Content-Type") != "application/websocket-events") {
             respondError(req, 400, "Bad Request",