diff --git a/app/controllers/metrics_controller.rb b/app/controllers/metrics_controller.rb
index 4ff77603..785044c0 100644
--- a/app/controllers/metrics_controller.rb
+++ b/app/controllers/metrics_controller.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class MetricsController < ApplicationController
-  http_basic_authenticate_with name: ENV['METRICS_USERNAME'], password: ENV['METRICS_PASSWORD'], only: :index
+  http_basic_authenticate_with name: METRICS_USERNAME, password: METRICS_PASSWORD, only: :index
 
   def index
     result = PrometheusMetrics.fetch_data
diff --git a/config/initializers/01_constants.rb b/config/initializers/01_constants.rb
index 594cadb3..1129be64 100644
--- a/config/initializers/01_constants.rb
+++ b/config/initializers/01_constants.rb
@@ -31,3 +31,8 @@ STORE_GEODATA = ENV.fetch('STORE_GEODATA', 'true') == 'true'
 
 SENTRY_DSN = ENV.fetch('SENTRY_DSN', nil)
 MANAGER_URL = SELF_HOSTED ? nil : ENV.fetch('MANAGER_URL', nil)
+
+# Prometheus metrics
+METRICS_USERNAME = ENV.fetch('METRICS_USERNAME', 'prometheus')
+METRICS_PASSWORD = ENV.fetch('METRICS_PASSWORD', 'prometheus')
+# /Prometheus metrics