diff --git a/frontend/src/ts/constants/env-config.ts b/frontend/src/ts/constants/env-config.ts
index 9bf3a8da086e..98a192a12427 100644
--- a/frontend/src/ts/constants/env-config.ts
+++ b/frontend/src/ts/constants/env-config.ts
@@ -2,6 +2,7 @@ type Config = {
   backendUrl: string;
   isDevelopment: boolean;
   clientVersion: string;
+  recaptchaSiteKey: string;
 };
 
 //@ts-expect-error these get replaced by vite
@@ -10,9 +11,12 @@ const backendUrl = BACKEND_URL;
 const isDevelopment = IS_DEVELOPMENT;
 // @ts-expect-error
 const clientVersion = CLIENT_VERSION;
+// @ts-expect-error
+const recaptchaSiteKey = RECAPTCHA_SITE_KEY;
 
 export const envConfig: Config = {
   backendUrl,
   isDevelopment,
   clientVersion,
+  recaptchaSiteKey,
 };
diff --git a/frontend/src/ts/controllers/captcha-controller.ts b/frontend/src/ts/controllers/captcha-controller.ts
index 497d92f831a6..09ed2b68a5db 100644
--- a/frontend/src/ts/controllers/captcha-controller.ts
+++ b/frontend/src/ts/controllers/captcha-controller.ts
@@ -1,4 +1,5 @@
-const siteKey = "6Lc-V8McAAAAAJ7s6LGNe7MBZnRiwbsbiWts87aj";
+import { envConfig } from "../constants/env-config";
+const siteKey = envConfig.recaptchaSiteKey;
 
 const captchas: Record<string, number> = {};
 
diff --git a/frontend/vite.config.js b/frontend/vite.config.js
index aa2dcd0d5a29..4106d33316c8 100644
--- a/frontend/vite.config.js
+++ b/frontend/vite.config.js
@@ -121,6 +121,9 @@ const BASE_CONFIG = {
     ),
     IS_DEVELOPMENT: JSON.stringify(true),
     CLIENT_VERSION: JSON.stringify("DEVELOPMENT_CLIENT"),
+    RECAPTCHA_SITE_KEY: JSON.stringify(
+      "6LeIxAcTAAAAAJcZVRqyHh71UMIEGNQ_MXjiZKhI"
+    ),
   },
   optimizeDeps: {
     include: ["jquery"],
@@ -190,11 +193,15 @@ const BUILD_CONFIG = {
     BACKEND_URL: JSON.stringify("https://api.monkeytype.com"),
     IS_DEVELOPMENT: JSON.stringify(false),
     CLIENT_VERSION: JSON.stringify(buildClientVersion()),
+    RECAPTCHA_SITE_KEY: JSON.stringify(process.env.RECAPTCHA_SITE_KEY),
   },
 };
 
 export default defineConfig(({ command }) => {
   if (command === "build") {
+    if (process.env.RECAPTCHA_SITE_KEY === undefined) {
+      throw new Error(".env: RECAPTCHA_SITE_KEY is not defined");
+    }
     return mergeConfig(BASE_CONFIG, BUILD_CONFIG);
   } else {
     return BASE_CONFIG;