diff --git a/sources/MVCFramework.RESTClient.Intf.pas b/sources/MVCFramework.RESTClient.Intf.pas
index cb107573..9109e66c 100644
--- a/sources/MVCFramework.RESTClient.Intf.pas
+++ b/sources/MVCFramework.RESTClient.Intf.pas
@@ -146,6 +146,7 @@ type
     /// </param>
     function AddHeader(const aName, aValue: string): IMVCRESTClient; overload;
     function HeaderValue(const aName: string): string;
+    function Headers: TNameValueArray;
 
     /// <summary>
     /// Clears all headers.
diff --git a/sources/MVCFramework.RESTClient.pas b/sources/MVCFramework.RESTClient.pas
index 40cdeaad..8adc3a70 100644
--- a/sources/MVCFramework.RESTClient.pas
+++ b/sources/MVCFramework.RESTClient.pas
@@ -63,6 +63,8 @@ type
   TCookies = System.Net.HttpClient.TCookies;
   TURLRequest = System.Net.URLClient.TURLRequest;
   TCertificate = System.Net.URLClient.TCertificate;
+  TNameValuePair = System.Net.URLClient.TNameValuePair;
+  TNameValueArray = System.Net.URLClient.TNameValueArray;
   IHTTPRequest = System.Net.HttpClient.IHTTPRequest;
   IHTTPResponse = System.Net.HttpClient.IHTTPResponse;
 
@@ -76,12 +78,6 @@ type
     fHTTPClient: THTTPClient;
     fBaseURL: string;
     fResource: string;
-    fAccept: string;
-    fAcceptCharset: string;
-    fAcceptEncoding: string;
-    fUserAgent: string;
-    fContentType: string;
-    fAuthorization: string;
     fProxySettings: TProxySettings;
     fParameters: TList<TMVCRESTParam>;
     fRawBody: TStringStream;
@@ -225,6 +221,7 @@ type
     /// </param>
     function AddHeader(const aName, aValue: string): IMVCRESTClient; overload;
     function HeaderValue(const aName: string): string;
+    function Headers: TNameValueArray;
 
     /// <summary>
     /// Clears all headers.
@@ -522,35 +519,32 @@ type
 
 function TMVCRESTClient.Accept: string;
 begin
-  Result := fAccept;
+  Result := HeaderValue(sAccept);
 end;
 
 function TMVCRESTClient.Accept(const aAccept: string): IMVCRESTClient;
 begin
-  Result := Self;
-  fAccept := aAccept;
+  Result := AddHeader(sAccept, aAccept);
 end;
 
 function TMVCRESTClient.AcceptCharset: string;
 begin
-  Result := fAcceptCharset;
+  Result := HeaderValue(sAcceptCharset);
 end;
 
 function TMVCRESTClient.AcceptCharset(const aAcceptCharset: string): IMVCRESTClient;
 begin
-  Result := Self;
-  fAcceptCharset := aAcceptCharset;
+  Result := AddHeader(sAcceptCharset, aAcceptCharset);
 end;
 
 function TMVCRESTClient.AcceptEncoding(const aAcceptEncoding: string): IMVCRESTClient;
 begin
-  Result := Self;
-  fAcceptEncoding := aAcceptEncoding;
+  Result := AddHeader(sAcceptEncoding, aAcceptEncoding);
 end;
 
 function TMVCRESTClient.AcceptEncoding: string;
 begin
-  Result := fAcceptEncoding;
+  Result := HeaderValue(sAcceptEncoding);
 end;
 
 function TMVCRESTClient.AddBody(const aBody: string; const aContentType: string): IMVCRESTClient;
@@ -767,7 +761,7 @@ end;
 
 function TMVCRESTClient.Authorization: string;
 begin
-  Result := fAuthorization;
+  Result := HeaderValue(sAuthorization);
 end;
 
 function TMVCRESTClient.BaseURL(const aBaseURL: string): IMVCRESTClient;
@@ -792,11 +786,20 @@ begin
 end;
 
 function TMVCRESTClient.ClearAllParams: IMVCRESTClient;
+var
+  lAuthorization: string;
 begin
   Result := Self;
+
+  lAuthorization := HeaderValue(sAuthorization);
   fParameters.Clear;
   ClearBody;
 
+  AddHeader(sAccept, TMVCRESTClientConsts.DEFAULT_ACCEPT);
+  AddHeader(sAcceptEncoding, TMVCRESTClientConsts.DEFAULT_ACCEPT_ENCODING);
+  AddHeader(sUserAgent, TMVCRESTClientConsts.DEFAULT_USER_AGENT);
+  AddHeader(sAuthorization, lAuthorization);
+
   fNextRequestIsAsync := False;
   fAsyncCompletionHandler := nil;
   fAsyncCompletionHandlerWithError := nil;
@@ -806,7 +809,7 @@ end;
 function TMVCRESTClient.ClearAuthorization: IMVCRESTClient;
 begin
   Result := Self;
-  fAuthorization := '';
+  AddHeader(sAuthorization, '');
 end;
 
 function TMVCRESTClient.ClearBody: IMVCRESTClient;
@@ -817,7 +820,7 @@ begin
 
   Result := Self;
   ClearParameters(TMVCRESTParamType.FormURLEncoded);
-  fContentType := '';
+  AddHeader(sContentType, '');
 end;
 
 function TMVCRESTClient.ClearCookies: IMVCRESTClient;
@@ -896,13 +899,6 @@ begin
   fBaseURL := '';
   fResource := '';
 
-  fAccept := TMVCRESTClientConsts.DEFAULT_ACCEPT;
-  fAcceptCharset := '';
-  fAcceptEncoding := TMVCRESTClientConsts.DEFAULT_ACCEPT_ENCODING;
-  fUserAgent := TMVCRESTClientConsts.DEFAULT_USER_AGENT;
-  fContentType := '';
-  fAuthorization := '';
-
   ClearAllParams;
 end;
 
@@ -1003,14 +999,6 @@ begin
       fHTTPClient.CustomHeaders[lParam.Name] := lParam.Value;
     end;
   end;
-  if not fAuthorization.IsEmpty then
-  begin
-    fHTTPClient.CustomHeaders[TMVCRESTClientConsts.AUTHORIZATION_HEADER] := fAuthorization;
-  end;
-  fHTTPClient.Accept := fAccept;
-  fHTTPClient.AcceptCharSet := fAcceptCharset;
-  fHTTPClient.AcceptEncoding := fAcceptEncoding;
-  fHTTPClient.ContentType := fContentType;
 end;
 
 procedure TMVCRESTClient.DoApplyPathParams(var aURL: string);
@@ -1083,6 +1071,7 @@ end;
 
 procedure TMVCRESTClient.DoPrepareBodyRequest(var aBodyStream: TStream);
 var
+  lCurrentContentType: string;
   lContentType: string;
   lContentCharset: string;
   lParam: TMVCRESTParam;
@@ -1090,7 +1079,8 @@ var
   lValue: string;
   lBody: string;
 begin
-  SplitContentMediaTypeAndCharset(fContentType, lContentType, lContentCharset);
+  lCurrentContentType := HeaderValue(sContentType);
+  SplitContentMediaTypeAndCharset(lCurrentContentType, lContentType, lContentCharset);
 
   if SameText(lContentType, TMVCMediaType.MULTIPART_FORM_DATA) then
   begin
@@ -1111,7 +1101,7 @@ begin
         lBody := lBody + lName + '=' + lValue;
       end;
     end;
-    AddBody(lBody, fContentType);
+    AddBody(lBody, lCurrentContentType);
     aBodyStream := fRawBody;
   end
   else
@@ -1281,6 +1271,26 @@ begin
   Result := Head;
 end;
 
+function TMVCRESTClient.Headers: TNameValueArray;
+var
+  lHeaders: TList<TNameValuePair>;
+  lParam: TMVCRESTParam;
+begin
+  lHeaders := TList<TNameValuePair>.Create;
+  try
+    for lParam in fParameters do
+    begin
+      if lParam.&Type = TMVCRESTParamType.Header then
+      begin
+        lHeaders.Add(TNameValuePair.Create(lParam.Name, lParam.Value));
+      end;
+    end;
+    Result := lHeaders.ToArray;
+  finally
+    FreeAndNil(lHeaders);
+  end;
+end;
+
 function TMVCRESTClient.HeaderValue(const aName: string): string;
 var
   lParam: TMVCRESTParam;
@@ -1634,7 +1644,7 @@ begin
   // Do not use TNetEncoding.Base64 here, because it may break long line
   lBase64 := TBase64Encoding.Create(0, '');
   try
-    fAuthorization := TMVCRESTClientConsts.BASIC_AUTH_PREFIX + lBase64.Encode(aUsername + ':' + aPassword);
+    AddHeader(sAuthorization, TMVCRESTClientConsts.BASIC_AUTH_PREFIX + lBase64.Encode(aUsername + ':' + aPassword));
   finally
     FreeAndNil(lBase64);
   end;
@@ -1642,8 +1652,7 @@ end;
 
 function TMVCRESTClient.SetBearerAuthorization(const aAccessToken: string): IMVCRESTClient;
 begin
-  Result := Self;
-  fAuthorization := TMVCRESTClientConsts.BEARER_AUTH_PREFIX + aAccessToken;
+  Result := AddHeader(sAuthorization, TMVCRESTClientConsts.BEARER_AUTH_PREFIX + aAccessToken);
 end;
 
 function TMVCRESTClient.SetBeforeRequestProc(aBeforeRequestProc: TBeforeRequestProc): IMVCRESTClient;
@@ -1654,7 +1663,7 @@ end;
 
 procedure TMVCRESTClient.SetContentType(const aContentType: string);
 begin
-  fContentType := aContentType;
+  AddHeader(sContentType, aContentType);
 end;
 
 procedure TMVCRESTClient.SetParameter(const aParamType: TMVCRESTParamType; const aName, aValue: string);
@@ -1669,7 +1678,6 @@ begin
       Break;
     end;
   end;
-
   fParameters.Add(TMVCRESTParam.Create(aParamType, aName, aValue));
 end;
 
@@ -1694,13 +1702,12 @@ end;
 
 function TMVCRESTClient.UserAgent(const aUserAgent: string): IMVCRESTClient;
 begin
-  Result := Self;
-  fUserAgent := aUserAgent;
+  Result := AddHeader(sUserAgent, aUserAgent);
 end;
 
 function TMVCRESTClient.UserAgent: string;
 begin
-  Result := fUserAgent;
+  Result := HeaderValue(sUserAgent);
 end;
 
 { TMVCRESTResponse }