diff --git a/app.js b/app.js
index 1dc65bc..169e5fa 100644
--- a/app.js
+++ b/app.js
@@ -20,6 +20,7 @@ if (cluster.isMaster) {
 } else {
     const express         = require('express');
     const bodyParser      = require('body-parser');
+    const cors            = require('cors');
     const http            = require('http');
     const path            = require('path');
     const app             = express();
@@ -33,6 +34,7 @@ if (cluster.isMaster) {
 
     app.set('port', process.env.PORT || 8080);
     app.use(helmet());
+    app.use(cors());
     app.use(bodyParser.json());
 
     // configure rate limiting
diff --git a/package-lock.json b/package-lock.json
index c57091b..9fcdedf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -512,6 +512,15 @@
       "resolved": "https://registry.npmjs.org/core-util-is/-/core-util-is-1.0.2.tgz",
       "integrity": "sha1-tf1UIgqivFq1eqtxQMlAdUUDwac="
     },
+    "cors": {
+      "version": "2.8.4",
+      "resolved": "https://registry.npmjs.org/cors/-/cors-2.8.4.tgz",
+      "integrity": "sha1-K9OB8usgECAQXNUOpZ2mMJBpRoY=",
+      "requires": {
+        "object-assign": "4.1.1",
+        "vary": "1.1.2"
+      }
+    },
     "create-error-class": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/create-error-class/-/create-error-class-3.0.2.tgz",
@@ -2694,6 +2703,11 @@
       "resolved": "https://registry.npmjs.org/oauth-sign/-/oauth-sign-0.8.2.tgz",
       "integrity": "sha1-Rqarfwrq2N6unsBWV4C31O/rnUM="
     },
+    "object-assign": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/object-assign/-/object-assign-4.1.1.tgz",
+      "integrity": "sha1-IQmtx5ZYh8/AXLvUQsrIv7s2CGM="
+    },
     "object-copy": {
       "version": "0.1.0",
       "resolved": "https://registry.npmjs.org/object-copy/-/object-copy-0.1.0.tgz",
diff --git a/package.json b/package.json
index 99a41d3..0043126 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,7 @@
   "homepage": "https://github.com/10a7/eth-gas-json#readme",
   "dependencies": {
     "body-parser": "^1.18.2",
+    "cors": "^2.8.4",
     "dotenv": "^4.0.0",
     "express": "^4.16.2",
     "express-rate-limit": "^2.11.0",