diff --git a/app/client-ecs.js b/app/client-ecs.js
index 49a45d4..2e4c589 100644
--- a/app/client-ecs.js
+++ b/app/client-ecs.js
@@ -25,8 +25,21 @@ export default class ClientEcs extends Ecs {
     return cache.get(uri);
   }
   async readJson(uri) {
-    const chars = await this.readAsset(uri);
-    return chars.byteLength > 0 ? JSON.parse((new TextDecoder()).decode(chars)) : {};
+    const key = ['$$json', uri].join(':');
+    if (!cache.has(key)) {
+      let promise, resolve, reject;
+      promise = new Promise((res, rej) => {
+        resolve = res;
+        reject = rej;
+      });
+      cache.set(key, promise);
+      this.readAsset(uri)
+        .then((chars) => {
+          resolve(chars.byteLength > 0 ? JSON.parse((new TextDecoder()).decode(chars)) : {});
+        })
+        .catch(reject);
+    }
+    return cache.get(key);
   }
   async readScript(uri, context = {}) {
     const code = await this.readAsset(uri);
diff --git a/app/engine.js b/app/engine.js
index fff04bc..390ac61 100644
--- a/app/engine.js
+++ b/app/engine.js
@@ -11,6 +11,12 @@ import createHomestead from './create-homestead.js';
 import createHouse from './create-house.js';
 import createPlayer from './create-player.js';
 
+import {LRUCache} from 'lru-cache';
+
+const cache = new LRUCache({
+  max: 128,
+});
+
 export default class Engine {
 
   connectedPlayers = new Map();
@@ -38,11 +44,35 @@ export default class Engine {
         return engine.frame;
       }
       async readAsset(uri) {
-        return server.readAsset(uri);
+        if (!cache.has(uri)) {
+          let promise, resolve, reject;
+          promise = new Promise((res, rej) => {
+            resolve = res;
+            reject = rej;
+          });
+          cache.set(uri, promise);
+          server.readAsset(uri)
+            .then(resolve)
+            .catch(reject);
+        }
+        return cache.get(uri);
       }
       async readJson(uri) {
-        const chars = await this.readAsset(uri);
-        return chars.byteLength > 0 ? JSON.parse((new TextDecoder()).decode(chars)) : {};
+        const key = ['$$json', uri].join(':');
+        if (!cache.has(key)) {
+          let promise, resolve, reject;
+          promise = new Promise((res, rej) => {
+            resolve = res;
+            reject = rej;
+          });
+          cache.set(key, promise);
+          this.readAsset(uri)
+            .then((chars) => {
+              resolve(chars.byteLength > 0 ? JSON.parse((new TextDecoder()).decode(chars)) : {});
+            })
+            .catch(reject);
+        }
+        return cache.get(key);
       }
       async readScript(uri, context) {
         if (!uri) {