diff --git a/cic_syncer/client/evm/__pycache__/response.cpython-38.pyc b/cic_syncer/client/evm/__pycache__/response.cpython-38.pyc
index 7a8de2b..0813207 100644
Binary files a/cic_syncer/client/evm/__pycache__/response.cpython-38.pyc and b/cic_syncer/client/evm/__pycache__/response.cpython-38.pyc differ
diff --git a/cic_syncer/client/evm/__pycache__/websocket.cpython-38.pyc b/cic_syncer/client/evm/__pycache__/websocket.cpython-38.pyc
index faac392..289ec78 100644
Binary files a/cic_syncer/client/evm/__pycache__/websocket.cpython-38.pyc and b/cic_syncer/client/evm/__pycache__/websocket.cpython-38.pyc differ
diff --git a/cic_syncer/client/evm/response.py b/cic_syncer/client/evm/response.py
index 7e87340..0d4e72c 100644
--- a/cic_syncer/client/evm/response.py
+++ b/cic_syncer/client/evm/response.py
@@ -1,7 +1,11 @@
+import json
+
 from cic_syncer.client import translate
 
+
 translations = {
-        'block_number': 'hex_to_int',
+        'block_number': translate.hex_to_int,
+        'get_block': json.dumps,
         }
 
 
@@ -10,7 +14,7 @@ class EVMResponse:
     def __init__(self, item, response_object):
         self.response_object = response_object
         self.item = item
-        self.fn = getattr(translate, translations[self.item])
+        self.fn = translations[self.item]
 
 
     def get_error(self):
diff --git a/cic_syncer/client/evm/websocket.py b/cic_syncer/client/evm/websocket.py
index 11d389d..5b81282 100644
--- a/cic_syncer/client/evm/websocket.py
+++ b/cic_syncer/client/evm/websocket.py
@@ -1,3 +1,4 @@
+import logging
 import uuid
 import json
 
@@ -6,6 +7,7 @@ import websocket
 from .response import EVMResponse
 from cic_syncer.error import RequestError
 
+logg = logging.getLogger()
 
 
 class EVMWebsocketClient:
@@ -35,3 +37,23 @@ class EVMWebsocketClient:
             raise RequestError(err)
 
         return res.get_result()
+
+
+    def get_block_by_integer(self, n):
+        req_id = str(uuid.uuid4())
+        nhx = '0x' + n.to_bytes(8, 'big').hex()
+        req = {
+                'jsonrpc': '2.0',
+                'method': 'eth_getBlockByNumber',
+                'id': str(req_id),
+                'params': [nhx, False],
+                }
+        self.conn.send(json.dumps(req))
+        r = self.conn.recv()
+        res = EVMResponse('get_block', json.loads(r))
+        err = res.get_error()
+        if err != None:
+            raise RequestError(err)
+
+        return res.get_result()
+
diff --git a/cic_syncer/driver.py b/cic_syncer/driver.py
index 97e76c1..6e5fb88 100644
--- a/cic_syncer/driver.py
+++ b/cic_syncer/driver.py
@@ -3,9 +3,6 @@ import uuid
 import logging
 import time
 
-# third-party imports
-import websockets
-
 logg = logging.getLogger()
 
 
@@ -36,10 +33,8 @@ class MinedSyncer(Syncer):
         super(MinedSyncer, self).__init__(backend)
 
 
-    def loop(self, interval):
+    def loop(self, interval, getter):
         while self.running and Syncer.running_global:
-            getter = self.backend.connect()
-            logg.debug('loop execute')
             e = self.get(getter)
             time.sleep(interval)
 
@@ -53,17 +48,9 @@ class HeadSyncer(MinedSyncer):
     def get(self, getter):
         (block_number, tx_number) = self.backend.get()
         block_hash = []
-        try:
-            uu = uuid.uuid4()
-            req = {
-                    'jsonrpc': '2.0',
-                    'method': 'eth_getBlock',
-                    'id': str(uu),
-                    'param': [block_number],
-                    }
-            logg.debug(req)
-        except Exception as e:
-            logg.error(e)
+        uu = uuid.uuid4()
+        res = getter.get_block_by_integer(block_number)
+        logg.debug(res)
 
         return block_hash
 
diff --git a/cic_syncer/runnable/tracker.py b/cic_syncer/runnable/tracker.py
index 1ca57f1..e842647 100644
--- a/cic_syncer/runnable/tracker.py
+++ b/cic_syncer/runnable/tracker.py
@@ -97,9 +97,7 @@ chain = args.i
 
 
 def main(): 
-
     block_offset = c.block_number()
-    logg.debug('block offset {}'.format(block_offset))
 
     syncer_backend = SyncerBackend.live(chain, block_offset+1)
     syncer = HeadSyncer(syncer_backend)
@@ -113,7 +111,8 @@ def main():
         syncer.filter.append(task_pair)
 
     try:
-        syncer.loop(int(config.get('SYNCER_LOOP_INTERVAL')))
+        logg.debug('block offset {} {}'.format(block_offset, c))
+        syncer.loop(int(config.get('SYNCER_LOOP_INTERVAL')), c)
     except LoopDone as e:
         sys.stderr.write("sync '{}' done at block {}\n".format(args.mode, e))