diff --git a/package-lock.json b/package-lock.json
index db0dd63..c08e27a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,7 @@
       "name": "silphius",
       "version": "1.0.0",
       "dependencies": {
+        "@msgpack/msgpack": "^3.0.0-beta2",
         "@pixi/react": "^7.1.2",
         "pixi.js": "^8.1.5",
         "react": "^18.3.1",
@@ -2634,6 +2635,14 @@
         "react": ">=16"
       }
     },
+    "node_modules/@msgpack/msgpack": {
+      "version": "3.0.0-beta2",
+      "resolved": "https://registry.npmjs.org/@msgpack/msgpack/-/msgpack-3.0.0-beta2.tgz",
+      "integrity": "sha512-y+l1PNV0XDyY8sM3YtuMLK5vE3/hkfId+Do8pLo/OPxfxuFAUwcGz3oiiUuV46/aBpwTzZ+mRWVMtlSKbradhw==",
+      "engines": {
+        "node": ">= 14"
+      }
+    },
     "node_modules/@ndelangen/get-tarball": {
       "version": "3.0.9",
       "resolved": "https://registry.npmjs.org/@ndelangen/get-tarball/-/get-tarball-3.0.9.tgz",
diff --git a/package.json b/package.json
index e108d8a..6f67798 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
     "vitest": "^1.6.0"
   },
   "dependencies": {
+    "@msgpack/msgpack": "^3.0.0-beta2",
     "@pixi/react": "^7.1.2",
     "pixi.js": "^8.1.5",
     "react": "^18.3.1",
diff --git a/src/components/pixi.jsx b/src/components/pixi.jsx
index 24926e4..5c6476a 100644
--- a/src/components/pixi.jsx
+++ b/src/components/pixi.jsx
@@ -9,6 +9,11 @@ import ClientContext from '../context/client';
 import Entities from './entities';
 import styles from './pixi.module.css';
 
+import {Ecs} from '../ecs/index.js';
+import * as Components from '../ecs/components.js';
+
+const ecs = new Ecs(Components);
+
 export default function Pixi() {
   const client = useContext(ClientContext);
   const [entities, setEntities] = useState([]);
@@ -21,7 +26,18 @@ export default function Pixi() {
           break;
         }
         case 'tick': {
-          setEntities(payload.entities);
+          const {buffer, byteLength, byteOffset} = payload.entities;
+          const view = new DataView(buffer, byteOffset, byteLength);
+          ecs.decode(view);
+          const entities = [];
+          for (const entity of ecs.entities) {
+            const {Position, Visible} = ecs.get(entity);
+            entities.push({
+              image: Visible.image,
+              position: [Position.x, Position.y],
+            })
+          }
+          setEntities(entities);
           break;
         }
         default:
diff --git a/src/components/silphius.jsx b/src/components/silphius.jsx
index c3720da..33ba5d4 100644
--- a/src/components/silphius.jsx
+++ b/src/components/silphius.jsx
@@ -15,10 +15,10 @@ export default function Silphius() {
       let Client;
       switch (connectionTuple[0]) {
         case 'local':
-          ({default: Client} = await import('../client/local.js'));
+          ({default: Client} = await import('../net/client/local.js'));
           break;
         case 'remote':
-          ({default: Client} = await import('../client/remote.js'));
+          ({default: Client} = await import('../net/client/remote.js'));
           break;
       }
       const client = new Client();
diff --git a/src/components/ui.jsx b/src/components/ui.jsx
index 828e9de..51695ae 100644
--- a/src/components/ui.jsx
+++ b/src/components/ui.jsx
@@ -1,7 +1,7 @@
 import {useContext, useEffect} from 'react';
 
 import addKeyListener from '../add-key-listener.js';
-import {RESOLUTION} from '../constants';
+import {ACTION_MAP, RESOLUTION} from '../constants';
 import ClientContext from '../context/client';
 import Dom from './dom';
 import Pixi from './pixi';
@@ -9,13 +9,6 @@ import styles from './ui.module.css';
 
 const ratio = RESOLUTION[0] / RESOLUTION[1];
 
-// Handle input.
-const ACTION_MAP = {
-  w: 'moveUp',
-  d: 'moveRight',
-  s: 'moveDown',
-  a: 'moveLeft',
-};
 const KEY_MAP = {
   keyDown: 1,
   keyUp: 0,
diff --git a/src/constants.js b/src/constants.js
index ed870a4..d7d729a 100644
--- a/src/constants.js
+++ b/src/constants.js
@@ -2,3 +2,17 @@ export const RESOLUTION = [
   800,
   450,
 ];
+
+export const ACTION_MAP = {
+  w: 'moveUp',
+  d: 'moveRight',
+  s: 'moveDown',
+  a: 'moveLeft',
+};
+
+export const MOVE_MAP = {
+  'moveUp': 'up',
+  'moveRight': 'right',
+  'moveDown': 'down',
+  'moveLeft': 'left',
+};
diff --git a/src/server/ecs/bundle.js b/src/ecs/bundle.js
similarity index 100%
rename from src/server/ecs/bundle.js
rename to src/ecs/bundle.js
diff --git a/src/server/ecs/chain.js b/src/ecs/chain.js
similarity index 100%
rename from src/server/ecs/chain.js
rename to src/ecs/chain.js
diff --git a/src/server/ecs/chain.test.js b/src/ecs/chain.test.js
similarity index 100%
rename from src/server/ecs/chain.test.js
rename to src/ecs/chain.test.js
diff --git a/src/server/ecs/component.js b/src/ecs/component.js
similarity index 100%
rename from src/server/ecs/component.js
rename to src/ecs/component.js
diff --git a/src/server/ecs/component.test.js b/src/ecs/component.test.js
similarity index 100%
rename from src/server/ecs/component.test.js
rename to src/ecs/component.test.js
diff --git a/src/server/ecs/component/arbitrary.js b/src/ecs/component/arbitrary.js
similarity index 100%
rename from src/server/ecs/component/arbitrary.js
rename to src/ecs/component/arbitrary.js
diff --git a/src/server/ecs/component/arbitrary.test.js b/src/ecs/component/arbitrary.test.js
similarity index 100%
rename from src/server/ecs/component/arbitrary.test.js
rename to src/ecs/component/arbitrary.test.js
diff --git a/src/server/ecs/component/base.js b/src/ecs/component/base.js
similarity index 100%
rename from src/server/ecs/component/base.js
rename to src/ecs/component/base.js
diff --git a/src/server/ecs/component/flat.js b/src/ecs/component/flat.js
similarity index 100%
rename from src/server/ecs/component/flat.js
rename to src/ecs/component/flat.js
diff --git a/src/server/ecs/component/flat.test.js b/src/ecs/component/flat.test.js
similarity index 100%
rename from src/server/ecs/component/flat.test.js
rename to src/ecs/component/flat.test.js
diff --git a/src/ecs/components.js b/src/ecs/components.js
new file mode 100644
index 0000000..2397e22
--- /dev/null
+++ b/src/ecs/components.js
@@ -0,0 +1,17 @@
+export const Controlled = {
+  up: 'float32',
+  right: 'float32',
+  down: 'float32',
+  left: 'float32',
+};
+
+export const Position = {
+  x: 'float32',
+  y: 'float32',
+};
+
+export const Visible = {
+  image: 'string',
+};
+
+export const Wandering = {};
diff --git a/src/server/ecs/ecs.js b/src/ecs/ecs.js
similarity index 100%
rename from src/server/ecs/ecs.js
rename to src/ecs/ecs.js
diff --git a/src/server/ecs/ecs.test.js b/src/ecs/ecs.test.js
similarity index 100%
rename from src/server/ecs/ecs.test.js
rename to src/ecs/ecs.test.js
diff --git a/src/server/ecs/entity-factory.js b/src/ecs/entity-factory.js
similarity index 100%
rename from src/server/ecs/entity-factory.js
rename to src/ecs/entity-factory.js
diff --git a/src/server/ecs/index.js b/src/ecs/index.js
similarity index 100%
rename from src/server/ecs/index.js
rename to src/ecs/index.js
diff --git a/src/server/ecs/query.js b/src/ecs/query.js
similarity index 100%
rename from src/server/ecs/query.js
rename to src/ecs/query.js
diff --git a/src/server/ecs/query.test.js b/src/ecs/query.test.js
similarity index 100%
rename from src/server/ecs/query.test.js
rename to src/ecs/query.test.js
diff --git a/src/server/ecs/schema.js b/src/ecs/schema.js
similarity index 100%
rename from src/server/ecs/schema.js
rename to src/ecs/schema.js
diff --git a/src/server/ecs/schema.test.js b/src/ecs/schema.test.js
similarity index 100%
rename from src/server/ecs/schema.test.js
rename to src/ecs/schema.test.js
diff --git a/src/server/ecs/serializer.js b/src/ecs/serializer.js
similarity index 100%
rename from src/server/ecs/serializer.js
rename to src/ecs/serializer.js
diff --git a/src/server/ecs/serializer.test.js b/src/ecs/serializer.test.js
similarity index 100%
rename from src/server/ecs/serializer.test.js
rename to src/ecs/serializer.test.js
diff --git a/src/server/ecs/system.js b/src/ecs/system.js
similarity index 100%
rename from src/server/ecs/system.js
rename to src/ecs/system.js
diff --git a/src/index.js b/src/index.js
index f3cf467..04b3bab 100644
--- a/src/index.js
+++ b/src/index.js
@@ -3,6 +3,8 @@ import {createRoot} from 'react-dom/client';
 
 import Silphius from './components/silphius.jsx';
 
+await import('./isomorphinit.js');
+
 // Setup DOM.
 createRoot(document.querySelector('.silphius'))
   .render(createElement(Silphius));
diff --git a/src/isomorphinit.js b/src/isomorphinit.js
new file mode 100644
index 0000000..546396b
--- /dev/null
+++ b/src/isomorphinit.js
@@ -0,0 +1,7 @@
+// Gathering.
+const {default: PacketClass} = await import('./net/packet/packet.js');
+Object.values(await import('./net/packet/packets.js'))
+  .forEach((Packet) => {
+    PacketClass.register(Packet);
+  });
+PacketClass.mapRegistered();
diff --git a/src/client/client.js b/src/net/client/client.js
similarity index 64%
rename from src/client/client.js
rename to src/net/client/client.js
index 83c0a47..23087e8 100644
--- a/src/client/client.js
+++ b/src/net/client/client.js
@@ -1,10 +1,13 @@
+import Packet from "../packet/packet";
+
 export default class Client {
   constructor() {
     this.listeners = [];
   }
-  accept(data) {
+  accept(packed) {
+    const decoded = Packet.accept(packed);
     for (const i in this.listeners) {
-      this.listeners[i](data);
+      this.listeners[i](decoded);
     }
   }
   addMessageListener(listener) {
@@ -16,4 +19,7 @@ export default class Client {
       this.listeners.splice(index, 1);
     }
   }
+  send(packet) {
+    this.transmit(Packet.transmit(packet));
+  }
 }
diff --git a/src/client/local.js b/src/net/client/local.js
similarity index 59%
rename from src/client/local.js
rename to src/net/client/local.js
index 5605cb6..319df6b 100644
--- a/src/client/local.js
+++ b/src/net/client/local.js
@@ -2,12 +2,12 @@ import Client from './client.js';
 
 export default class LocalClient extends Client {
   async connect() {
-    this.worker = new Worker('../server/worker.js', {type: 'module'});
+    this.worker = new Worker('/net/server/worker.js', {type: 'module'});
     this.worker.onmessage = (event) => {
       this.accept(event.data);
     };
   }
-  send(message) {
-    this.worker.postMessage(message);
+  transmit(packed) {
+    this.worker.postMessage(packed);
   }
 }
diff --git a/src/client/remote.js b/src/net/client/remote.js
similarity index 71%
rename from src/client/remote.js
rename to src/net/client/remote.js
index 34647d9..81145aa 100644
--- a/src/client/remote.js
+++ b/src/net/client/remote.js
@@ -3,15 +3,15 @@ import Client from './client.js';
 export default class RemoteClient extends Client {
   async connect() {
     this.socket = new WebSocket(`ws://${window.location.host}/ws`);
+    this.socket.binaryType = 'arraybuffer';
     this.socket.onmessage = (event) => {
-      this.accept(JSON.parse(event.data));
+      this.accept(event.data);
     };
     await new Promise((resolve) => {
       this.socket.onopen = resolve;
     });
   }
-  send(message) {
-    this.socket.send(JSON.stringify(message));
+  transmit(packed) {
+    this.socket.send(packed);
   }
 }
-
diff --git a/src/net/packet/action.js b/src/net/packet/action.js
new file mode 100644
index 0000000..08b4aff
--- /dev/null
+++ b/src/net/packet/action.js
@@ -0,0 +1,33 @@
+import Packet from "./packet.js";
+
+const WIRE_MAP = {
+  'moveUp': 0,
+  'moveRight': 1,
+  'moveDown': 2,
+  'moveLeft': 3,
+};
+Object.entries(WIRE_MAP)
+  .forEach(([k, v]) => {
+    WIRE_MAP[v] = k;
+  });
+
+export default class Action extends Packet {
+
+  static type = 'action';
+
+  static pack(payload) {
+    return super.pack({
+      type: WIRE_MAP[payload.type],
+      value: payload.value,
+    });
+  }
+
+  static unpack(packed) {
+    const unpacked = super.unpack(packed);
+    return {
+      type: WIRE_MAP[unpacked.type],
+      value: unpacked.value,
+    };
+  }
+
+};
diff --git a/src/net/packet/connect.js b/src/net/packet/connect.js
new file mode 100644
index 0000000..911a3f2
--- /dev/null
+++ b/src/net/packet/connect.js
@@ -0,0 +1,7 @@
+import Packet from "./packet.js";
+
+export default class Connect extends Packet {
+
+  static type = 'connect';
+
+};
diff --git a/src/net/packet/connected.js b/src/net/packet/connected.js
new file mode 100644
index 0000000..36dde42
--- /dev/null
+++ b/src/net/packet/connected.js
@@ -0,0 +1,7 @@
+import Packet from "./packet.js";
+
+export default class Connected extends Packet {
+
+  static type = 'connected';
+
+};
diff --git a/src/net/packet/packet.js b/src/net/packet/packet.js
new file mode 100644
index 0000000..3f6ec76
--- /dev/null
+++ b/src/net/packet/packet.js
@@ -0,0 +1,68 @@
+import {encode, decode} from '@msgpack/msgpack';
+
+export default class Packet {
+
+  static registered = {};
+
+  constructor(payload = {}) {
+    this.payload = payload;
+  }
+
+  static accept(packed) {
+    const decoded = decode(packed);
+    const Packet = this.registered[decoded.id];
+    return {
+      type: Packet.type,
+      payload: Packet.unpack(decoded),
+    };
+  }
+
+  static decode(buffer) {
+    try {
+      return this.unpack(decode(buffer));
+    }
+    catch (error) {
+      throw new Error(`decoding ${this.type}: ${error.message}`);
+    }
+  }
+
+  static encode(payload) {
+    try {
+      return encode(this.pack(payload));
+    }
+    catch (error) {
+      throw new Error(`encoding ${this.type}: ${error.message}`);
+    }
+  }
+
+  static mapRegistered() {
+    this.registered = Object.fromEntries([
+      ...Object.entries(this.registered),
+      ...Object.entries(this.registered)
+        .map(([type, Packet], id) => {
+          Packet.id = id;
+          return [id, Packet];
+        }),
+    ]);
+  }
+
+  static pack(payload) {
+    return {
+      id: this.id,
+      payload,
+    };
+  }
+
+  static register(Packet) {
+    this.registered[Packet.type] = Packet;
+  }
+
+  static transmit({type, payload}) {
+    return this.registered[type].encode(payload);
+  }
+
+  static unpack({payload}) {
+    return payload;
+  }
+
+}
diff --git a/src/net/packet/packets.js b/src/net/packet/packets.js
new file mode 100644
index 0000000..8f6a13f
--- /dev/null
+++ b/src/net/packet/packets.js
@@ -0,0 +1,4 @@
+export {default as Action} from './action.js';
+export {default as Connect} from './connect.js';
+export {default as Connected} from './connected.js';
+export {default as Tick} from './tick.js';
diff --git a/src/net/packet/tick.js b/src/net/packet/tick.js
new file mode 100644
index 0000000..d59de34
--- /dev/null
+++ b/src/net/packet/tick.js
@@ -0,0 +1,7 @@
+import Packet from "./packet.js";
+
+export default class Tick extends Packet {
+
+  static type = 'tick';
+
+};
diff --git a/src/net/server/cell.js b/src/net/server/cell.js
new file mode 100644
index 0000000..ec96fd5
--- /dev/null
+++ b/src/net/server/cell.js
@@ -0,0 +1,11 @@
+import {Ecs} from '../../ecs/index.js';
+import * as Components from '../../ecs/components.js';
+
+export default class Cell {
+  constructor() {
+    this.ecs = new Ecs(Components);
+  }
+  tick(elapsed) {
+    this.ecs.tick(elapsed);
+  }
+}
\ No newline at end of file
diff --git a/src/net/server/server.js b/src/net/server/server.js
new file mode 100644
index 0000000..5222623
--- /dev/null
+++ b/src/net/server/server.js
@@ -0,0 +1,119 @@
+import {MOVE_MAP} from '../../constants.js';
+import Cell from './cell.js';
+import {Ecs, System} from '../../ecs/index.js';
+import * as Components from '../../ecs/components.js';
+import Packet from "../packet/packet.js";
+
+const SPEED = 100;
+const TPS = 60;
+
+await import ('../../isomorphinit.js');
+
+class MovementSystem extends System {
+
+  static queries() {
+    return {
+      default: ['Position', 'Controlled'],
+    };
+  }
+
+  tick(elapsed) {
+    for (const [position, controlled] of this.select('default')) {
+      position.x += SPEED * elapsed * (controlled.right - controlled.left);
+      position.y += SPEED * elapsed * (controlled.down - controlled.up);
+    }
+  }
+
+}
+
+export default class Server {
+
+  constructor() {
+    this.cells = [new Cell()];
+    this.cells[0].ecs.addSystem(MovementSystem);
+    this.connections = [];
+    this.connectedPlayers = new Map();
+    this.frame = 0;
+    this.last = Date.now();
+  }
+
+  accept(connection, packed) {
+    const decoded = Packet.accept(packed);
+    const {payload, type} = decoded;
+    switch (type) {
+      case 'connect': {
+        this.send(
+          connection,
+          {
+            type: 'connected',
+            payload: [],
+          },
+        );
+        break;
+      }
+      case 'action': {
+        const {ecs} = this.cells[0];
+        const connectedPlayer = this.connectedPlayers.get(connection);
+        if (payload.type in MOVE_MAP) {
+          ecs.get(connectedPlayer).Controlled[MOVE_MAP[payload.type]] = payload.value;
+        }
+        break;
+      }
+      default:
+    }
+  }
+
+  connectPlayer(connection) {
+    this.connections.push(connection);
+    const {ecs} = this.cells[0];
+    const entity = ecs.create({
+      Controlled: {up: 0, right: 0, down: 0, left: 0},
+      Position: {x: 50, y: 50},
+      Visible: {image: './assets/bunny.png'},
+    })
+    this.connectedPlayers.set(connection, entity);
+  }
+
+  disconnectPlayer(connection) {
+    const entity = this.connectedPlayers.get(connection);
+    this.connectedPlayers.delete(connection);
+    this.connections.splice(this.connections.indexOf(connection), 1);
+  }
+
+  async load() {
+  }
+
+  send(connection, packet) {
+    this.transmit(connection, Packet.transmit(packet));
+  }
+
+  start() {
+    return setInterval(() => {
+      const elapsed = (Date.now() - this.last) / 1000;
+      this.last = Date.now();
+      this.tick(elapsed);
+    }, 1000 / TPS);
+  }
+
+  tick(elapsed) {
+    this.cells[0].ecs.tick(elapsed);
+    const {ecs} = this.cells[0];
+    const view = new DataView(new ArrayBuffer(ecs.sizeOf(ecs.entities)));
+    ecs.encode(ecs.entities, view);
+    for (const connection of this.connections) {
+      this.send(
+        connection,
+        {
+          type: 'tick',
+          payload: {
+            entities: view,
+            elapsed,
+            frame: this.frame,
+          },
+        },
+      );
+    }
+    this.frame += 1;
+  }
+
+}
diff --git a/src/server/socket.js b/src/net/server/socket.js
similarity index 78%
rename from src/server/socket.js
rename to src/net/server/socket.js
index 3dd3895..a4d3f05 100644
--- a/src/server/socket.js
+++ b/src/net/server/socket.js
@@ -9,7 +9,7 @@ const {
 const wss = new WebSocketServer({port: SILPHIUS_WEBSOCKET_PORT});
 
 const server = new class SocketServer extends Server {
-  send(ws, data) { ws.send(JSON.stringify(data)); }
+  transmit(ws, packed) { ws.send(packed); }
 }
 
 await server.load();
@@ -20,7 +20,7 @@ wss.on('connection', function connection(ws) {
   ws.on('close', () => {
     server.disconnectPlayer(ws);
   })
-  ws.on('message', (data) => {
-    server.accept(ws, JSON.parse(data));
+  ws.on('message', (packed) => {
+    server.accept(ws, packed);
   });
 });
diff --git a/src/server/worker.js b/src/net/server/worker.js
similarity index 57%
rename from src/server/worker.js
rename to src/net/server/worker.js
index 8a79688..1eac253 100644
--- a/src/server/worker.js
+++ b/src/net/server/worker.js
@@ -1,7 +1,7 @@
 import Server from './server.js';
 
 const server = new class WorkerServer extends Server {
-  send(connection, data) { postMessage(data); }
+  transmit(connection, packed) { postMessage(packed); }
 }
 
 await server.load();
@@ -9,4 +9,4 @@ server.start();
 
 server.connectPlayer(undefined);
 
-onmessage = ({data}) => { server.accept(undefined, data); };
+onmessage = (event) => { server.accept(undefined, event.data); };
diff --git a/src/server/server.js b/src/server/server.js
deleted file mode 100644
index cdb97af..0000000
--- a/src/server/server.js
+++ /dev/null
@@ -1,89 +0,0 @@
-const SPEED = 100;
-const TPS = 20;
-
-const MOVE_MAP = {
-  'moveUp': 0,
-  'moveRight': 1,
-  'moveDown': 2,
-  'moveLeft': 3,
-};
-
-export default class Server {
-
-  constructor() {
-    this.connections = [];
-    this.connectedPlayers = new Map();
-    this.entities = [];
-    this.frame = 0;
-    this.last = Date.now();
-  }
-
-  accept(connection, {type, payload}) {
-    switch (type) {
-      case 'connect': {
-        this.send(connection, {type: 'connected', payload: Array.from(this.connectedPlayers.values())});
-        break;
-      }
-      case 'action': {
-        const connectedPlayer = this.connectedPlayers.get(connection);
-        if (payload.type in MOVE_MAP) {
-          connectedPlayer.movement[MOVE_MAP[payload.type]] = payload.value;
-        }
-        break;
-      }
-      default:
-    }
-  }
-
-  connectPlayer(connection) {
-    this.connections.push(connection);
-    const entity = {
-      image: './assets/bunny.png',
-      movement: [0, 0, 0, 0],
-      position: [50, 50],
-    };
-    this.entities.push(entity);
-    this.connectedPlayers.set(connection, entity);
-  }
-
-  disconnectPlayer(connection) {
-    const entity = this.connectedPlayers.get(connection);
-    this.connectedPlayers.delete(connection);
-    this.connections.splice(this.connections.indexOf(connection), 1);
-    this.entities.splice(this.entities.indexOf(entity), 1);
-  }
-
-  async load() {
-  }
-
-  start() {
-    return setInterval(() => {
-      const elapsed = (Date.now() - this.last) / 1000;
-      this.last = Date.now();
-      this.tick(elapsed);
-    }, 1000 / TPS);
-  }
-
-  tick(elapsed) {
-    for (const connection of this.connections) {
-      const {movement, position} = this.connectedPlayers.get(connection);
-      position[0] += SPEED * elapsed * (movement[1] - movement[3]);
-      position[1] += SPEED * elapsed * (movement[2] - movement[0]);
-    }
-    for (const connection of this.connections) {
-      this.send(
-        connection,
-        {
-          type: 'tick',
-          payload: {
-            entities: this.entities,
-            elapsed,
-            frame: this.frame,
-          },
-        },
-      );
-    }
-    this.frame += 1;
-  }
-
-}