diff --git a/backend/entrypoint.sh b/backend/entrypoint.sh
index 5d44345fda..20441c58fb 100755
--- a/backend/entrypoint.sh
+++ b/backend/entrypoint.sh
@@ -29,11 +29,15 @@ if [ "$migrate" = true ]; then
     .venv/bin/python manage.py migrate
 fi
 
-# Configure Gunicorn based on --dev flag
+# Configure Gunicorn based on --dev flag.
+# Threads must exceed concurrent browser tabs — each open Socket.IO WebSocket
+# holds one thread for its lifetime. The pool spawns threads lazily, so a high
+# ceiling is free at idle.
 gunicorn_args=(
     --bind 0.0.0.0:8000
-    --workers 2
-    --threads 2
+    --workers "${GUNICORN_WORKERS:-2}"
+    --threads "${GUNICORN_THREADS:-512}"
+    --worker-class gthread
     --log-level debug
     --timeout 600
     --access-logfile -
diff --git a/backend/sample.env b/backend/sample.env
index b57101813e..700422d1a4 100644
--- a/backend/sample.env
+++ b/backend/sample.env
@@ -7,6 +7,11 @@ CSRF_COOKIE_SECURE=False
 # Default log level
 DEFAULT_LOG_LEVEL="INFO"
 
+# Gunicorn tuning. GUNICORN_THREADS must exceed concurrent browser tabs —
+# each open Socket.IO WebSocket holds one thread for its lifetime.
+GUNICORN_WORKERS=2
+GUNICORN_THREADS=512
+
 # Common
 PATH_PREFIX="api/v1"