diff --git a/README.md b/README.md
index 401e8c38..cc7f7050 100644
--- a/README.md
+++ b/README.md
@@ -657,21 +657,22 @@ Requires:
 
 The `http` service allows GET and POST requests to an HTTP service.
 
-Each target has four parameters:
+Each target has five parameters:
 
 1. The HTTP method (one of `get` or `post`)
 2. The URL, which is transformed if possible (transformation errors are ignored)
 3. `None` or a dict of parameters. Each individual parameter value is transformed.
 4. `None` or a list of username/password e.g. `( 'username', 'password')`
+5. `None` or True to force the transformation of the third parameter to a json object
 
 ```ini
 [config:http]
 timeout = 60
 
 targets = {
-                #method     #URL               # query params or None          # list auth
+                #method     #URL               # query params or None                              # list auth # Json
   'get1'    : [ "get",  "http://example.org?", { 'q': '{name}', 'isod' : '{_dtiso}', 'xx': 'yy' }, ('username', 'password') ],
-  'post1'    : [ "post", "http://example.net", { 'q': '{name}', 'isod' : '{_dtiso}', 'xx': 'yy' }, None ]
+  'post1'    : [ "post", "http://example.net", { 'q': '{name}', 'isod' : '{_dtiso}', 'xx': 'yy' }, None, True ]
   }
 ```
 
diff --git a/services/http.py b/services/http.py
index 5722d203..00e41e22 100644
--- a/services/http.py
+++ b/services/http.py
@@ -14,7 +14,7 @@
     import simplejson as json
 
 def plugin(srv, item):
-    ''' addrs: (method, url dict(params), list(username, password)) '''
+    ''' addrs: (method, url, dict(params), list(username, password), json) '''
 
     srv.logging.debug("*** MODULE=%s: service=%s, target=%s", __file__, item.service, item.target)
 
@@ -30,6 +30,12 @@ def plugin(srv, item):
     except:
         pass
 
+    tojson = None
+    try:
+        tojson = item.addrs[4]
+    except:
+        pass
+
     # Try and transform the URL. Use original URL if it's not possible
     try:
         url = url.format(**item.data)
@@ -82,7 +88,10 @@ def plugin(srv, item):
         try:
             request = urllib2.Request(url)
             if params is not None:
-                encoded_params = urllib.urlencode(params)
+                if tojson is not None:
+                    encoded_params = json.dumps(params)
+                else:
+                    encoded_params = urllib.urlencode(params)
             else:
                 encoded_params = message