diff --git a/README.md b/README.md
index 694ddf34..a74b7773 100644
--- a/README.md
+++ b/README.md
@@ -62,6 +62,16 @@ The basic development workflow follows these steps:
 - Pages load the appropriate flow from `components/flow/`.
 - They do not contain UI or logic directly, just route level layout or guards.
 
+### Validation
+
+- UI level validation in `components/app`. help users avoid mistakes before submitting.
+  - Lightweight/instant validation related to UX.
+  - Basic formatting (email regex, numeric-only, password length).
+  - Showing error messages directly under the field.
+
+- Business level validation in `components/flow`. cannot rely only on the UI, since it often requires server-side checks or rules that may change.
+  - More complex validation rules tied to business logic.
+
 ## Code Conventions
 
 - Under the script setup block, putting things in group with the following order: