diff --git a/client/index.js b/client/index.js
index 39d0fe0..a2e04e7 100644
--- a/client/index.js
+++ b/client/index.js
@@ -7,12 +7,14 @@ import {EntityList} from '@avocado/entity';
 import {ActionRegistry} from '@avocado/input';
 import {Stage} from '@avocado/graphics';
 import {Vector} from '@avocado/math';
+import {SocketIoParser} from '@avocado/packet';
 import {Synchronizer, Unpacker} from '@avocado/state';
 import {Room, RoomView} from '@avocado/topdown';
 import {World} from '@avocado/physics/matter/world';
 import {clearAnimation, setAnimation, Ticker} from '@avocado/timing';
 // 1st party.
 import {InputPacket, KeysPacket, StatePacket} from '../common/packet';
+import {augmentParserWithThroughput} from '../common/parser-throughput';
 import {WorldTime} from '../common/world-time';
 import Ui from './ui';
 // DOM.
@@ -38,11 +40,6 @@ stage.element.addEventListener('focus', () => {
 stage.addToDom(appNode);
 // World time ticker.
 const worldTimeTicker = new Ticker(1 / 10);
-// UI.
-const UiComponent = <Ui
-  worldTimeTicker={worldTimeTicker}
-/>;
-ReactDOM.render(UiComponent, stage.ui);
 // Handle "own" entity.
 let selfEntity;
 function hasSelfEntity() {
@@ -156,7 +153,22 @@ stage.on('pointerUp', (event) => {
 });
 let actionState = actionRegistry.state;
 // Create the socket connection.
-const socket = createClient(window.location.href);
+const AugmentedParser = augmentParserWithThroughput(SocketIoParser);
+const socket = createClient(window.location.href, {
+  parser: AugmentedParser,
+});
+// Throughput ticker.
+const throughputSampleTime = 0.5;
+const throughputTicker = new Ticker(throughputSampleTime);
+const {Decoder, Encoder} = AugmentedParser;
+throughputTicker.on('tick', () => {
+  throughputTicker.emit('updateThroughput', Vector.scale([
+    Decoder.throughput,
+    Encoder.throughput,
+  ], 1 / throughputSampleTime));
+  Decoder.throughput = 0;
+  Encoder.throughput = 0;
+});
 // Input messages.
 const messageHandle = setInterval(() => {
   // Mouse/touch movement.
@@ -199,6 +211,8 @@ const predictionHandle = setInterval(() => {
   renderTicker.tick(elapsed);
   // World time ticker.
   worldTimeTicker.tick(elapsed);
+  // Throughput ticker.
+  throughputTicker.tick(elapsed);
   // Apply environmental lighting.
   let intensity = 0;
   if (worldTime.hour >= 21 || worldTime.hour < 4) {
@@ -256,3 +270,9 @@ function render() {
   dirty = false;
 }
 const renderHandle = setAnimation(render);
+// UI.
+const UiComponent = <Ui
+  worldTimeTicker={worldTimeTicker}
+  throughputTicker={throughputTicker}
+/>;
+ReactDOM.render(UiComponent, stage.ui);
diff --git a/client/ui/index.js b/client/ui/index.js
index 47200ff..2573978 100644
--- a/client/ui/index.js
+++ b/client/ui/index.js
@@ -2,10 +2,14 @@
 import React from 'react';
 import {hot} from 'react-hot-loader/root';
 // 1st party.
+import Throughput from './throughput';
 import WorldTime from './world-time';
 
-const Ui = ({worldTimeTicker}) => {
-  return <WorldTime ticker={worldTimeTicker} />;
+const Ui = ({throughputTicker, worldTimeTicker}) => {
+  return <React.Fragment>
+    <WorldTime ticker={worldTimeTicker} />
+    <Throughput ticker={throughputTicker} />
+  </React.Fragment>;
 };
 
 export default hot(Ui);
diff --git a/client/ui/throughput.js b/client/ui/throughput.js
new file mode 100644
index 0000000..63351ec
--- /dev/null
+++ b/client/ui/throughput.js
@@ -0,0 +1,59 @@
+// 3rd party.
+import React, {useEffect, useState} from 'react';
+// 2nd party.
+import {compose} from '@avocado/core';
+import contempo from 'contempo';
+// 1st party.
+import {WorldTime} from '../../common/world-time';
+
+const decorate = compose(
+  contempo(`
+.throughput {
+  background-color: rgba(0, 0, 0, .3);
+  color: white;
+  font-size: 0.6em;
+  position: absolute;
+  top: 0.5em;
+  left: 0.5em;
+  line-height: 1em;
+  width: 11em;
+  padding: 0.5em;
+  font-family: monospace;
+}
+.throughput .input:before {
+  content: 'kbps \\a0in: ';
+}
+.throughput .output:before {
+  content: 'kbps out: ';
+}
+.throughput p {
+  margin: 0.25em;
+}
+  `),
+);
+
+const formatKbps = (bytes) => {
+  const bps = bytes * 8;
+  const kbps = bps / 1000;
+  return Math.floor(kbps * 100) / 100;
+}
+
+const ThroughputComponent = ({ticker}) => {
+  const [throughput, setThroughput] = useState([0, 0]);
+  useEffect(() => {
+    const updater = (throughput) => {
+      setThroughput(throughput);
+    };
+    ticker.on('updateThroughput', updater);
+    return () => {
+      ticker.off('updateThroughput', updater);
+    };
+  }, []);
+  return <div className="throughput unselectable">
+    <p className="input">{formatKbps(throughput[0])}</p>
+    <p className="output">{formatKbps(throughput[1])}</p>
+
+  </div>;
+}
+
+export default decorate(ThroughputComponent);
diff --git a/common/parser-throughput.js b/common/parser-throughput.js
new file mode 100644
index 0000000..2d2e4c9
--- /dev/null
+++ b/common/parser-throughput.js
@@ -0,0 +1,20 @@
+
+export function augmentParserWithThroughput(Parser) {
+  const {Decoder, Encoder} = Parser;
+  // Decoder.
+  Decoder.throughput = 0;
+  const {parseBinary} = Decoder.prototype;
+  Decoder.prototype.parseBinary = function (obj) {
+    Decoder.throughput += obj.length || obj.byteLength;
+    return parseBinary.call(this, obj);
+  };
+  // Encoder.
+  Encoder.throughput = 0;
+  const {pack} = Encoder.prototype;
+  Encoder.prototype.pack = function (packet) {
+    const buffer = pack.call(this, packet);
+    Encoder.throughput += buffer.length || buffer.byteLength;
+    return buffer;
+  };
+  return Parser;
+}
\ No newline at end of file