diff --git a/kkkmeet-server.el b/kkkmeet-server.el
index 7a8cc8f..c57d1ab 100644
--- a/kkkmeet-server.el
+++ b/kkkmeet-server.el
@@ -2,7 +2,7 @@
 
 ;; Run from a shell:
 ;;   emacs -Q --batch -l kkkmeet-server.el -f kkkmeet-server-run-batch
-;;   KKKMEET_CAPTCHA_PASSPHRASE=secret emacs -Q --batch -l kkkmeet-server.el -f kkkmeet-server-run-batch
+;;   CAPTCHA=secret emacs -Q --batch -l kkkmeet-server.el -f kkkmeet-server-run-batch
 ;;
 ;; Or from Emacs:
 ;;   M-x kkkmeet-server-start
@@ -131,7 +131,7 @@
 
 (defun kkkmeet-server--captcha-passphrase ()
   "Return the configured join captcha passphrase."
-  (or (getenv "KKKMEET_CAPTCHA_PASSPHRASE") "kkkmeet"))
+  (or (getenv "CAPTCHA") "kkkmeet"))
 
 (defun kkkmeet-server--captcha-accepted-p (value)
   "Return non-nil when VALUE matches the configured captcha passphrase."
diff --git a/public/index.html b/public/index.html
index e214ba6..707cd22 100644
--- a/public/index.html
+++ b/public/index.html
@@ -164,7 +164,7 @@
             <input
               id="captcha-input"
               autocomplete="off"
-              placeholder="Passphrase"
+              placeholder="Type captcha text here"
               required
             />
           </div>
diff --git a/server.js b/server.js
index 6243559..4b4f9b4 100644
--- a/server.js
+++ b/server.js
@@ -5,7 +5,7 @@ import { randomUUID } from "node:crypto";
 
 const port = Number(process.env.PORT || 3000);
 const host = process.env.HOST || "127.0.0.1";
-const captchaPassphrase = process.env.KKKMEET_CAPTCHA_PASSPHRASE || "kkkmeet";
+const captchaPassphrase = process.env.CAPTCHA || "kkkmeet";
 const publicDir = join(process.cwd(), "public");
 const rooms = new Map();
 const watchStates = new Map();