diff --git a/bin/correct_duplicate_addrs b/bin/correct_duplicate_addrs
index e71a4789daa140388fc0ded4f0f8fe9519a2ea86..b993c926666b4519e41437b7a172fa0263c9574a 100755
--- a/bin/correct_duplicate_addrs
+++ b/bin/correct_duplicate_addrs
@@ -10,7 +10,7 @@ require "redis"
 
 redis = Redis.new
 
-customer_id = ENV["DEFAULT_CUSTOMER_ID"]
+customer_id = ENV.fetch("DEFAULT_CUSTOMER_ID", nil)
 unless customer_id
 	puts "The env-var DEFAULT_CUSTOMER_ID must be set to the ID " \
 	     "of the customer who will receive the duplicated addrs, preferably " \
diff --git a/config.ru b/config.ru
index 6c96ddafb46aa4af10ffc09f15a7c0b43a320b8a..616528e769363170b8911a1e58c5555dce22f698 100644
--- a/config.ru
+++ b/config.ru
@@ -225,7 +225,7 @@ class CardVault
 end
 
 class JmpPay < Roda
-	SENTRY_DSN = ENV["SENTRY_DSN"] && URI(ENV["SENTRY_DSN"])
+	SENTRY_DSN = ENV.fetch("SENTRY_DSN", nil)&.then { |v| URI(v) }
 	plugin :render, engine: "slim"
 	plugin :cookies, path: "/"
 	plugin :common_logger, $stdout