diff --git a/roles/openshift-apps/fmn/templates/api.toml b/roles/openshift-apps/fmn/templates/api.toml
index 9832362b59..5e9edcd854 100644
--- a/roles/openshift-apps/fmn/templates/api.toml
+++ b/roles/openshift-apps/fmn/templates/api.toml
@@ -1,6 +1,14 @@
 amqp_url = "amqps://fmn{{ env_suffix }}:@rabbitmq{{ env_suffix }}.fedoraproject.org/%2Fpubsub"
 passive_declares = true
 
+# The topic_prefix configuration value will add a prefix to the topics of every sent message.
+# This is used for migrating from fedmsg, and should not be used afterwards.
+{% if env == "staging" %}
+topic_prefix = "org.fedoraproject.stg"
+{% else %}
+topic_prefix = "org.fedoraproject.prod"
+{% endif %}
+
 [tls]
 ca_cert = "/etc/pki/fedora-messaging/ca/cacert.pem"
 certfile = "/etc/pki/fedora-messaging/crt/fmn-cert.pem"