diff --git a/conn.go b/conn.go
index 44257b296183419bcb7a2c8e2f6ea91f5978a5de..9f97edadc5afb86b6474b24ebc8dec6208f44f70 100644
--- a/conn.go
+++ b/conn.go
@@ -2,6 +2,8 @@ package jrpc
 
 import "context"
 
+var _ Conn = (*Client)(nil)
+
 type Conn interface {
 	Call(ctx context.Context, result any, method string, params ...any) error
 	BatchCall(ctx context.Context, b ...BatchElem) error