diff --git a/web3.nim b/web3.nim
index 377b13d..b1cb022 100644
--- a/web3.nim
+++ b/web3.nim
@@ -87,28 +87,18 @@ func getValue(params: RequestParamsRx, field: string, FieldType: type):
   except CatchableError as exc:
     return err(exc.msg)
 
-func toJsonString(params: RequestParamsRx):
-       Result[JsonString, string] {.gcsafe, raises: [].} =
-  try:
-    let res = JrpcSys.encode(params.toTx)
-    return ok(res.JsonString)
-  except CatchableError as exc:
-    return err(exc.msg)
-
 proc handleSubscriptionNotification(w: Web3, params: RequestParamsRx):
                                 Result[void, string] {.gcsafe, raises: [].} =
   let subs = params.getValue("subscription", string).valueOr:
     return err(error)
   let s = w.subscriptions.getOrDefault(subs)
   if not s.isNil and not s.removed:
+    let res = params.getValue("result", JsonString).valueOr:
+      return err(error)
     if s.historicalEventsProcessed:
-      let res = params.getValue("result", JsonString).valueOr:
-        return err(error)
       s.eventHandler(res)
     else:
-      let par = params.toJsonString().valueOr:
-        return err(error)
-      s.pendingEvents.add(par)
+      s.pendingEvents.add(res)
 
   ok()
 
diff --git a/web3/contract_dsl.nim b/web3/contract_dsl.nim
index 4a1db4f..b39115b 100644
--- a/web3/contract_dsl.nim
+++ b/web3/contract_dsl.nim
@@ -2,6 +2,7 @@ import
   std/[macros, strutils],
   json_serialization,
   ./[encoding, eth_api_types],
+  ./conversions,
   stint,
   stew/byteutils
 
@@ -40,6 +41,12 @@ type
     of constructor: constructorObject: ConstructorObject
     of event: eventObject: EventObject
 
+  EventData* = object
+    data*: seq[byte]
+    topics*: seq[Bytes32]
+
+EventData.useDefaultSerializationIn JrpcConv
+
 proc joinStrings(s: varargs[string]): string = join(s)
 
 proc unknownType() = discard # Used for informative errors
@@ -233,7 +240,7 @@ proc genEvent(cname: NimNode, eventObject: EventObject): NimNode =
   if not eventObject.anonymous:
     let callbackIdent = ident "callback"
     let jsonIdent = ident "j"
-    let jsonData = ident "jsonData"
+    let eventData = ident "eventData"
     var
       params = nnkFormalParams.newTree(newEmptyNode())
       paramsWithRawData = nnkFormalParams.newTree(newEmptyNode())
@@ -243,10 +250,9 @@ proc genEvent(cname: NimNode, eventObject: EventObject): NimNode =
       call = nnkCall.newTree(callbackIdent)
       callWithRawData = nnkCall.newTree(callbackIdent)
       offset = ident "offset"
-      inputData = ident "inputData"
 
     argParseBody.add quote do:
-      let `jsonData` = JrpcConv.decode(`jsonIdent`.string, JsonNode)
+      let `eventData` = JrpcConv.decode(`jsonIdent`.string, EventData)
 
     var offsetInited = false
 
@@ -264,19 +270,18 @@ proc genEvent(cname: NimNode, eventObject: EventObject): NimNode =
       if input.indexed:
         argParseBody.add quote do:
           var `argument`: `kind`
-          discard decode(hexToSeqByte(`jsonData`["topics"][`i`].getStr), 0, 0, `argument`)
+          discard decode(`eventData`.topics[`i`].data, 0, 0, `argument`)
         i += 1
       else:
         if not offsetInited:
           argParseBody.add quote do:
-            var `inputData` = hexToSeqByte(`jsonData`["data"].getStr)
             var `offset` = 0
 
           offsetInited = true
 
         argParseBody.add quote do:
           var `argument`: `kind`
-          `offset` += decode(`inputData`, 0, `offset`, `argument`)
+          `offset` += decode(`eventData`.data, 0, `offset`, `argument`)
       call.add argument
       callWithRawData.add argument
     let