diff --git a/src/api/mod.rs b/src/api/mod.rs
index 16beee1..7d6eb8c 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -1,5 +1,5 @@
 use axum::{routing::post, Json, Router};
-use jsonwebtoken::{encode, EncodingKey, Header};
+use jsonwebtoken::{encode, DecodingKey, EncodingKey, Header};
 use rusqlite::Connection;
 use serde::Deserialize;
 use serde::Serialize;
@@ -13,11 +13,12 @@ pub fn get_routes() -> Router {
         "/api",
         Router::new()
             .route("/register", post(register))
-            .route("/login", post(login)),
+            .route("/login", post(login))
+            .route("/change_username", post(change_username)),
     )
 }
 
-#[derive(Serialize)]
+#[derive(Serialize, Deserialize)]
 struct Claims {
     account_id: usize,
     exp: usize,
@@ -121,3 +122,41 @@ pub async fn login(Json(payload): Json<LoginPayload>) -> Json<Value> {
         }
     }
 }
+
+#[derive(Deserialize)]
+pub struct ChangeUsernamePayload {
+    username: String,
+    token: String,
+}
+
+fn get_account_id_from_jwt(token: &str) -> Result<usize, jsonwebtoken::errors::Error> {
+    let jwt_secret = std::env::var("JWT_SECRET").expect("JWT_SECRET must be set");
+    let token_data = jsonwebtoken::decode::<Claims>(
+        token,
+        &DecodingKey::from_secret(jwt_secret.as_ref()),
+        &jsonwebtoken::Validation::default(),
+    )?;
+    Ok(token_data.claims.account_id)
+}
+
+pub async fn change_username(Json(payload): Json<ChangeUsernamePayload>) -> Json<Value> {
+    let account_id = match get_account_id_from_jwt(&payload.token) {
+        Ok(account_id) => account_id,
+        Err(_) => return Json(json!({ "error": "Invalid token" })),
+    };
+
+    let connection = Connection::open("database.db").expect("Failed to open database");
+    match db::change_username(&connection, account_id, &payload.username) {
+        Ok(_) => {}
+        Err(rusqlite::Error::SqliteFailure(_, _)) => {
+            connection.close().expect("Failed to close");
+            return Json(json!({ "error": "Username already taken" }));
+        }
+        Err(_) => {
+            connection.close().expect("Failed to close");
+            return Json(json!({ "error": "Failed to change username" }));
+        }
+    }
+    connection.close().expect("Failed to close");
+    Json(json!({ "success": "Username changed with success" }))
+}