diff --git a/internal/pubsub/broker.go b/internal/pubsub/broker.go
index 470d4d4..5c07f9d 100644
--- a/internal/pubsub/broker.go
+++ b/internal/pubsub/broker.go
@@ -7,7 +7,7 @@ import (
 	"github.com/leg100/pug/internal/resource"
 )
 
-const bufferSize = 1024
+const bufferSize = 1024 * 1024
 
 type Logger interface {
 	Debug(msg string, args ...any)