diff --git a/src/client/mod.rs b/src/client/mod.rs
new file mode 100644
index 0000000..924d651
--- /dev/null
+++ b/src/client/mod.rs
@@ -0,0 +1,52 @@
+use crate::core::sign_in::with_default_scopes;
+use std::error::Error;
+
+pub struct LogtoConfig<'a> {
+    pub endpoint: String,
+    pub app_id: String,
+    pub scopes: Option<Vec<&'a str>>,
+    pub resources: Option<Vec<&'a str>>,
+    pub prompt: Option<&'a str>,
+}
+struct AccessToken<'a> {
+    token: &'a str,
+    scope: &'a str,
+    expires_at: u32,
+}
+
+impl<'a> LogtoConfig<'a> {
+    /// Normalizes the Logto client configuration per the following rules:
+    /// - Add default scopes (`openid`, `offline_access` and `profile`) if not provided.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # use logto_rs::client::LogtoConfig;
+    /// let mut logto_config: LogtoConfig = LogtoConfig {
+    ///     endpoint: "https://logto.dev/api".to_string(),
+    ///     app_id: "app_id_value".to_string(),
+    ///     scopes: Some(vec!["email"]),
+    ///     resources: Some(vec!["resource 1"]),
+    ///     prompt: Some("prompt_value")
+    /// };
+    ///
+    /// let logto_config = logto_config.normalize().unwrap();
+    ///
+    /// assert_eq!(logto_config.scopes, Some(vec!["email", "offline_access", "openid", "profile"]))
+    ///
+    /// ```
+    pub fn normalize(&mut self) -> Result<Self, Box<dyn Error>> {
+        Ok(LogtoConfig {
+            endpoint: self.endpoint.clone(),
+            app_id: self.app_id.clone(),
+            scopes: Some(with_default_scopes(self.scopes.clone())),
+            resources: self.resources.clone(),
+            prompt: self.prompt.clone(),
+        })
+    }
+}
+
+struct LogtoClient<'a> {
+    logto_config: LogtoConfig<'a>,
+    access_token: AccessToken<'a>,
+}
diff --git a/src/core/mod.rs b/src/core/mod.rs
index a9ec9eb..8348c75 100644
--- a/src/core/mod.rs
+++ b/src/core/mod.rs
@@ -1,5 +1,5 @@
 mod fetch_token;
 mod oicd_config;
 mod revoke;
-mod sign_in;
+pub mod sign_in;
 mod sign_out;
diff --git a/src/core/sign_in.rs b/src/core/sign_in.rs
index 286736d..9807ed2 100644
--- a/src/core/sign_in.rs
+++ b/src/core/sign_in.rs
@@ -48,7 +48,7 @@ impl ReservedScopes {
     }
 }
 
-fn with_default_scopes(mut scopes: Option<Vec<&str>>) -> Vec<&str> {
+pub fn with_default_scopes(mut scopes: Option<Vec<&str>>) -> Vec<&str> {
     let default_scopes: Vec<&str> = vec![
         ReservedScopes::OfflineAccess.as_str(),
         ReservedScopes::OpenId.as_str(),
diff --git a/src/lib.rs b/src/lib.rs
index 0b43446..7087778 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,2 +1,3 @@
+pub mod client;
 mod core;
 mod utils;