diff --git a/cmd/tester/README.md b/cmd/tester/README.md
index 4d08ee8..7e3b7eb 100644
--- a/cmd/tester/README.md
+++ b/cmd/tester/README.md
@@ -1,7 +1,23 @@
 ## tester example
 
+Test and emit to the "payment.received" topic
+
+```sh
+go build
+export PASSWORD="Your gateway password"
+./tester \
+    -username=admin \
+    -password=$PASSWORD
+```
+
+Emit a custom topic:
+
 ```sh
 go build
 export PASSWORD="Your gateway password"
-./tester -username=admin -password=$PASSWORD
+
+./tester \
+    -username=admin \
+    -password=$PASSWORD \
+    -topic "custom/topic/1"
 ```