diff --git a/README.md b/README.md
index 7e8d2256..f844e836 100644
--- a/README.md
+++ b/README.md
@@ -44,6 +44,12 @@ If you want to mirror the I2P website, thanks! Here is a checklist:
   (look in `etc/update.vars` for the filename, your webserver should restart
   WSGI when the timestamp of this file changes).
 
+## Configuration
+
+Configuration files for the various scripts are in `etc/`. Environment variables
+in `etc/translation.vars` can be overridden by creating the file
+`etc/translation.vars.custom` and re-defining the environment variables there.
+
 ## Updating translations
 
 1. Pull new and updated translations from Transifex:
diff --git a/compile-messages.sh b/compile-messages.sh
index f3f2eb3a..40192ae9 100755
--- a/compile-messages.sh
+++ b/compile-messages.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 . ./etc/translation.vars
+[ -f ./etc/translation.vars.custom ] && . ./etc/translation.vars.custom
 
 export TZ=UTC
 
diff --git a/extract-messages.sh b/extract-messages.sh
index bdb277be..8ed9b88f 100755
--- a/extract-messages.sh
+++ b/extract-messages.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 . ./etc/translation.vars
+[ -f ./etc/translation.vars.custom ] && . ./etc/translation.vars.custom
 
 export TZ=UTC
 
diff --git a/init-new-po.sh b/init-new-po.sh
index e8395ac2..43c6c0a1 100755
--- a/init-new-po.sh
+++ b/init-new-po.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 . ./etc/translation.vars
+[ -f ./etc/translation.vars.custom ] && . ./etc/translation.vars.custom
 
 export TZ=UTC
 
diff --git a/update-existing-po.sh b/update-existing-po.sh
index decca88d..49584c18 100755
--- a/update-existing-po.sh
+++ b/update-existing-po.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 . ./etc/translation.vars
+[ -f ./etc/translation.vars.custom ] && . ./etc/translation.vars.custom
 export TZ=UTC
 
 if [ $# -ge 1 ]