diff --git a/templates/rust/examples/basic_usage.rs.twig b/templates/rust/examples/basic_usage.rs.twig
index 16b6cff627..6afb9b9e77 100644
--- a/templates/rust/examples/basic_usage.rs.twig
+++ b/templates/rust/examples/basic_usage.rs.twig
@@ -11,9 +11,9 @@ use {{ sdk.cratePackage | default('appwrite') | rustCrateName }}::{
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     // Initialize the client
     let client = Client::new()
-        .set_endpoint("{{ spec.endpoint }}") // Your API Endpoint
-        .set_project("5df5acd0d48c2") // Your project ID
-        .set_key("919c2d18fb5d4...a2ae413da83346ad2"); // Your secret API key
+        .set_endpoint("{{ spec.endpoint }}")? // Your API Endpoint
+        .set_project("5df5acd0d48c2")? // Your project ID
+        .set_key("919c2d18fb5d4...a2ae413da83346ad2")?; // Your secret API key
 
     println!("🚀 {{ spec.title }} Rust SDK Example");
     println!("Connected to: {}", client.endpoint());
@@ -129,9 +129,9 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     // This will likely fail with invalid credentials
     let invalid_client = Client::new()
-        .set_endpoint("{{ spec.endpoint }}")
-        .set_project("invalid-project")
-        .set_key("invalid-key");
+        .set_endpoint("{{ spec.endpoint }}")?
+        .set_project("invalid-project")?
+        .set_key("invalid-key")?;
 
     let invalid_users = Users::new(&invalid_client);
 
diff --git a/templates/rust/src/client.rs.twig b/templates/rust/src/client.rs.twig
index 0c2c68016d..4fb7f8d439 100644
--- a/templates/rust/src/client.rs.twig
+++ b/templates/rust/src/client.rs.twig
@@ -88,9 +88,12 @@ impl Client {
     /// Create a new {{ spec.title }} client
     pub fn new() -> Self {
         let mut headers = HeaderMap::new();
+        // SAFETY: Spec-defined header values are compile-time constants and always valid ASCII.
 {% for key, header in spec.global.defaultHeaders %}
         headers.insert("{{ key }}", "{{ header }}".parse().unwrap());
 {% endfor %}
+        // SAFETY: SDK metadata values are also compile-time constants; OS/ARCH are
+        // guaranteed-valid ASCII from std::env::consts.
         headers.insert("user-agent", format!("{{ spec.title }}RustSDK/{{ sdk.version }} ({}; {})", std::env::consts::OS, std::env::consts::ARCH).parse().unwrap());
         headers.insert("x-sdk-name", "{{ sdk.name }}".parse().unwrap());
         headers.insert("x-sdk-platform", "{{ sdk.platform }}".parse().unwrap());
@@ -138,72 +141,93 @@ impl Client {
     }
 
     /// Set the API endpoint
-    pub fn set_endpoint<S: Into<String>>(&self, endpoint: S) -> Self {
+    pub fn set_endpoint<S: Into<String>>(&self, endpoint: S) -> Result<Self> {
         let endpoint = endpoint.into();
-        if !endpoint.starts_with("http://") && !endpoint.starts_with("https://") {
-            panic!("Invalid endpoint URL: {}. Endpoint must start with http:// or https://", endpoint);
+        let parsed = url::Url::parse(&endpoint).map_err(|e| {{ spec.title | caseUcfirst }}Error::new(
+            400,
+            format!("Invalid endpoint URL: {}", e),
+            None,
+            String::new(),
+        ))?;
+        if parsed.scheme() != "http" && parsed.scheme() != "https" {
+            return Err({{ spec.title | caseUcfirst }}Error::new(
+                400,
+                format!("Invalid endpoint URL scheme '{}': must be http or https", parsed.scheme()),
+                None,
+                String::new(),
+            ));
         }
         self.state.rcu(|state| {
             let mut next = (**state).clone();
             next.config.endpoint = endpoint.clone();
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Set the project ID
-    pub fn set_project<S: Into<String>>(&self, project: S) -> Self {
+    pub fn set_project<S: Into<String>>(&self, project: S) -> Result<Self> {
         let project = project.into();
+        let value: reqwest::header::HeaderValue = project.parse()
+            .map_err(|e| {{ spec.title | caseUcfirst }}Error::new(400, format!("Invalid header value for x-appwrite-project: {}", e), None, String::new()))?;
         self.state.rcu(|state| {
             let mut next = (**state).clone();
-            next.config.headers.insert("x-appwrite-project", project.clone().parse().unwrap());
+            next.config.headers.insert("x-appwrite-project", value.clone());
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Set the API key
-    pub fn set_key<S: Into<String>>(&self, key: S) -> Self {
+    pub fn set_key<S: Into<String>>(&self, key: S) -> Result<Self> {
         let key = key.into();
+        let value: reqwest::header::HeaderValue = key.parse()
+            .map_err(|e| {{ spec.title | caseUcfirst }}Error::new(400, format!("Invalid header value for x-appwrite-key: {}", e), None, String::new()))?;
         self.state.rcu(|state| {
             let mut next = (**state).clone();
-            next.config.headers.insert("x-appwrite-key", key.clone().parse().unwrap());
+            next.config.headers.insert("x-appwrite-key", value.clone());
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Set the JWT token
-    pub fn set_jwt<S: Into<String>>(&self, jwt: S) -> Self {
+    pub fn set_jwt<S: Into<String>>(&self, jwt: S) -> Result<Self> {
         let jwt = jwt.into();
+        let value: reqwest::header::HeaderValue = jwt.parse()
+            .map_err(|e| {{ spec.title | caseUcfirst }}Error::new(400, format!("Invalid header value for x-appwrite-jwt: {}", e), None, String::new()))?;
         self.state.rcu(|state| {
             let mut next = (**state).clone();
-            next.config.headers.insert("x-appwrite-jwt", jwt.clone().parse().unwrap());
+            next.config.headers.insert("x-appwrite-jwt", value.clone());
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Set the locale
-    pub fn set_locale<S: Into<String>>(&self, locale: S) -> Self {
+    pub fn set_locale<S: Into<String>>(&self, locale: S) -> Result<Self> {
         let locale = locale.into();
+        let value: reqwest::header::HeaderValue = locale.parse()
+            .map_err(|e| {{ spec.title | caseUcfirst }}Error::new(400, format!("Invalid header value for x-appwrite-locale: {}", e), None, String::new()))?;
         self.state.rcu(|state| {
             let mut next = (**state).clone();
-            next.config.headers.insert("x-appwrite-locale", locale.clone().parse().unwrap());
+            next.config.headers.insert("x-appwrite-locale", value.clone());
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Set the session
-    pub fn set_session<S: Into<String>>(&self, session: S) -> Self {
+    pub fn set_session<S: Into<String>>(&self, session: S) -> Result<Self> {
         let session = session.into();
+        let value: reqwest::header::HeaderValue = session.parse()
+            .map_err(|e| {{ spec.title | caseUcfirst }}Error::new(400, format!("Invalid header value for x-appwrite-session: {}", e), None, String::new()))?;
         self.state.rcu(|state| {
             let mut next = (**state).clone();
-            next.config.headers.insert("x-appwrite-session", session.clone().parse().unwrap());
+            next.config.headers.insert("x-appwrite-session", value.clone());
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Enable or disable self-signed certificates
@@ -245,23 +269,21 @@ impl Client {
     }
 
     /// Add a custom header
-    pub fn add_header<K: AsRef<str>, V: AsRef<str>>(&self, key: K, value: V) -> Self {
+    pub fn add_header<K: AsRef<str>, V: AsRef<str>>(&self, key: K, value: V) -> Result<Self> {
         use reqwest::header::{HeaderName, HeaderValue};
 
         let key = key.as_ref().to_string();
         let value = value.as_ref().to_string();
 
+        let header_name: HeaderName = key.parse()?;
+        let header_value: HeaderValue = value.parse()?;
+
         self.state.rcu(|state| {
             let mut next = (**state).clone();
-            if let (Ok(header_name), Ok(header_value)) = (
-                key.parse::<HeaderName>(),
-                value.parse::<HeaderValue>(),
-            ) {
-                next.config.headers.insert(header_name, header_value);
-            }
+            next.config.headers.insert(header_name.clone(), header_value.clone());
             Arc::new(next)
         });
-        self.clone()
+        Ok(self.clone())
     }
 
     /// Get a copy of the current request headers
@@ -915,10 +937,24 @@ mod tests {
     #[test]
     fn test_client_builder_pattern() {
         let client = Client::new()
-            .set_endpoint("https://custom.example.com/v1")
-            .set_project("test-project")
-            .set_key("test-key");
+            .set_endpoint("https://custom.example.com/v1").unwrap()
+            .set_project("test-project").unwrap()
+            .set_key("test-key").unwrap();
 
         assert_eq!(client.endpoint(), "https://custom.example.com/v1");
     }
+
+    #[test]
+    fn test_invalid_endpoint() {
+        let client = Client::new();
+        let err = client.set_endpoint("htp://cloud.appwrite.io/v1").unwrap_err();
+        assert_eq!(err.code, 400);
+        assert!(err.message.contains("Invalid endpoint URL"));
+    }
+
+    #[test]
+    fn test_invalid_header_value() {
+        let client = Client::new();
+        assert!(client.set_key("my\nkey").is_err());
+    }
 }
diff --git a/templates/rust/src/error.rs.twig b/templates/rust/src/error.rs.twig
index 26ee0be65f..4e5c37f77e 100644
--- a/templates/rust/src/error.rs.twig
+++ b/templates/rust/src/error.rs.twig
@@ -69,6 +69,18 @@ impl From<std::io::Error> for {{ spec.title | caseUcfirst }}Error {
     }
 }
 
+impl From<reqwest::header::InvalidHeaderValue> for {{ spec.title | caseUcfirst }}Error {
+    fn from(err: reqwest::header::InvalidHeaderValue) -> Self {
+        Self::new(400, format!("Invalid header value: {}", err), None, String::new())
+    }
+}
+
+impl From<reqwest::header::InvalidHeaderName> for {{ spec.title | caseUcfirst }}Error {
+    fn from(err: reqwest::header::InvalidHeaderName) -> Self {
+        Self::new(400, format!("Invalid header name: {}", err), None, String::new())
+    }
+}
+
 /// {{ spec.title }} specific error response structure
 #[derive(Debug, serde::Deserialize)]
 pub struct ErrorResponse {
diff --git a/templates/rust/src/lib.rs.twig b/templates/rust/src/lib.rs.twig
index 3616be4a57..cb443cba1c 100644
--- a/templates/rust/src/lib.rs.twig
+++ b/templates/rust/src/lib.rs.twig
@@ -19,9 +19,9 @@
 //! #[tokio::main]
 //! async fn main() -> Result<(), Box<dyn std::error::Error>> {
 //!     let client = Client::new()
-//!         .set_endpoint("{{ spec.endpoint }}")
-//!         .set_project("your-project-id")
-//!         .set_key("your-api-key");
+//!         .set_endpoint("{{ spec.endpoint }}")?
+//!         .set_project("your-project-id")?
+//!         .set_key("your-api-key")?;
 //!
 //!     // Use the client to make API calls
 //!     Ok(())
diff --git a/templates/rust/tests/tests.rs b/templates/rust/tests/tests.rs
index a10a0e1fad..11317ebb1c 100644
--- a/templates/rust/tests/tests.rs
+++ b/templates/rust/tests/tests.rs
@@ -8,10 +8,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let string_in_array = vec!["string in array".to_string()];
 
     let client = Client::new()
-        .set_endpoint("http://mockapi/v1")
-        .set_project("appwrite")
-        .set_key("apikey")
-        .add_header("Origin", "http://localhost");
+        .set_endpoint("http://mockapi/v1")?
+        .set_project("appwrite")?
+        .set_key("apikey")?
+        .add_header("Origin", "http://localhost")?;
 
     println!("\n\nTest Started");
     let sdk_headers = client.get_headers();
@@ -134,7 +134,16 @@ async fn test_general_service(client: &Client, string_in_array: &[String]) -> Re
         },
     }
 
-    println!("Invalid endpoint URL: htp://cloud.appwrite.io/v1");
+    match Client::new().set_endpoint("htp://cloud.appwrite.io/v1") {
+        Ok(_) => {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::Other,
+                "Expected validation failure for invalid endpoint but got Ok",
+            )
+            .into())
+        },
+        Err(e) => println!("{}", e.message),
+    }
 
     let _ = general.empty().await;