diff --git a/mitmproxy/addons/dumper.py b/mitmproxy/addons/dumper.py
index 87f45976b..dcac6b82e 100644
--- a/mitmproxy/addons/dumper.py
+++ b/mitmproxy/addons/dumper.py
@@ -27,9 +27,10 @@ def colorful(line, styles):
 
 
 class Dumper:
-    def __init__(self, outfile=sys.stdout):
+    def __init__(self, outfile=sys.stdout, errfile=sys.stderr):
         self.filter: flowfilter.TFilter = None
         self.outfp: typing.io.TextIO = outfile
+        self.errfp: typing.io.TextIO = errfile
 
     def load(self, loader):
         loader.add_option(
@@ -70,6 +71,11 @@ class Dumper:
         if self.outfp:
             self.outfp.flush()
 
+    def echo_error(self, text, **style):
+        click.secho(text, file=self.errfp, **style)
+        if self.errfp:
+            self.errfp.flush()
+
     def _echo_headers(self, headers):
         for k, v in headers.fields:
             k = strutils.bytes_to_escaped_str(k)
@@ -243,7 +249,7 @@ class Dumper:
             self.echo_flow(f)
 
     def websocket_error(self, f):
-        self.echo(
+        self.echo_error(
             "Error in WebSocket connection to {}: {}".format(
                 human.format_address(f.server_conn.address), f.error
             ),
@@ -268,7 +274,7 @@ class Dumper:
                 f.close_reason))
 
     def tcp_error(self, f):
-        self.echo(
+        self.echo_error(
             "Error in TCP connection to {}: {}".format(
                 human.format_address(f.server_conn.address), f.error
             ),
diff --git a/test/mitmproxy/addons/test_dumper.py b/test/mitmproxy/addons/test_dumper.py
index c24801e4b..7a41c7b97 100644
--- a/test/mitmproxy/addons/test_dumper.py
+++ b/test/mitmproxy/addons/test_dumper.py
@@ -32,37 +32,50 @@ def test_configure():
 
 def test_simple():
     sio = io.StringIO()
-    d = dumper.Dumper(sio)
+    sio_err = io.StringIO()
+    d = dumper.Dumper(sio, sio_err)
     with taddons.context(d) as ctx:
         ctx.configure(d, flow_detail=0)
         d.response(tflow.tflow(resp=True))
         assert not sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=1)
         d.response(tflow.tflow(resp=True))
         assert sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=1)
         d.error(tflow.tflow(err=True))
         assert sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=4)
         d.response(tflow.tflow(resp=True))
         assert sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=4)
         d.response(tflow.tflow(resp=True))
         assert "<<" in sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=4)
         d.response(tflow.tflow(err=True))
         assert "<<" in sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=4)
         flow = tflow.tflow()
@@ -75,6 +88,8 @@ def test_simple():
         d.response(flow)
         assert sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=4)
         flow = tflow.tflow(resp=tutils.tresp(content=b"{"))
@@ -83,6 +98,8 @@ def test_simple():
         d.response(flow)
         assert sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
         ctx.configure(d, flow_detail=4)
         flow = tflow.tflow()
@@ -92,6 +109,8 @@ def test_simple():
         d.response(flow)
         assert "content missing" in sio.getvalue()
         sio.truncate(0)
+        assert not sio_err.getvalue()
+        sio_err.truncate(0)
 
 
 def test_echo_body():
@@ -100,7 +119,8 @@ def test_echo_body():
     f.response.content = b"foo bar voing\n" * 100
 
     sio = io.StringIO()
-    d = dumper.Dumper(sio)
+    sio_err = io.StringIO()
+    d = dumper.Dumper(sio, sio_err)
     with taddons.context(d) as ctx:
         ctx.configure(d, flow_detail=3)
         d._echo_message(f.response)
@@ -110,7 +130,8 @@ def test_echo_body():
 
 def test_echo_request_line():
     sio = io.StringIO()
-    d = dumper.Dumper(sio)
+    sio_err = io.StringIO()
+    d = dumper.Dumper(sio, sio_err)
     with taddons.context(d) as ctx:
         ctx.configure(d, flow_detail=3, showhost=True)
         f = tflow.tflow(client_conn=None, server_conn=True, resp=True)
@@ -146,7 +167,8 @@ class TestContentView:
         with mock.patch("mitmproxy.contentviews.auto.ViewAuto.__call__") as va:
             va.side_effect = exceptions.ContentViewException("")
             sio = io.StringIO()
-            d = dumper.Dumper(sio)
+            sio_err = io.StringIO()
+            d = dumper.Dumper(sio, sio_err)
             with taddons.context(d) as ctx:
                 ctx.configure(d, flow_detail=4)
                 d.response(tflow.tflow())
@@ -155,7 +177,8 @@ class TestContentView:
 
 def test_tcp():
     sio = io.StringIO()
-    d = dumper.Dumper(sio)
+    sio_err = io.StringIO()
+    d = dumper.Dumper(sio, sio_err)
     with taddons.context(d) as ctx:
         ctx.configure(d, flow_detail=3, showhost=True)
         f = tflow.ttcpflow()
@@ -165,12 +188,13 @@ def test_tcp():
 
         f = tflow.ttcpflow(client_conn=True, err=True)
         d.tcp_error(f)
-        assert "Error in TCP" in sio.getvalue()
+        assert "Error in TCP" in sio_err.getvalue()
 
 
 def test_websocket():
     sio = io.StringIO()
-    d = dumper.Dumper(sio)
+    sio_err = io.StringIO()
+    d = dumper.Dumper(sio, sio_err)
     with taddons.context(d) as ctx:
         ctx.configure(d, flow_detail=3, showhost=True)
         f = tflow.twebsocketflow()
@@ -183,4 +207,4 @@ def test_websocket():
 
         f = tflow.twebsocketflow(client_conn=True, err=True)
         d.websocket_error(f)
-        assert "Error in WebSocket" in sio.getvalue()
+        assert "Error in WebSocket" in sio_err.getvalue()