diff --git a/rootfs/etc/confd/templates/dovecot-oauth2.conf.ext.tmpl b/rootfs/etc/confd/templates/dovecot-oauth2.conf.ext.tmpl
index c3fa543..e20b014 100644
--- a/rootfs/etc/confd/templates/dovecot-oauth2.conf.ext.tmpl
+++ b/rootfs/etc/confd/templates/dovecot-oauth2.conf.ext.tmpl
@@ -1,5 +1,6 @@
 tokeninfo_url = {{ getenv "TOKENINFO_URL" }}
 introspection_url = {{ getenv "INTROSPECTION_URL" }}
+introspection_mode = {{ getenv "INTROSPECTION_MODE" "post" }}
 #force_introspection = yes
 username_attribute = email
 tls_ca_cert_file = /etc/ssl/certs/ca-certificates.crt