diff --git a/src/api/v1/auth/mod.rs b/src/api/v1/auth/mod.rs
index bfd32af..25910de 100644
--- a/src/api/v1/auth/mod.rs
+++ b/src/api/v1/auth/mod.rs
@@ -25,8 +25,7 @@ static EMAIL_REGEX: LazyLock<Regex> = LazyLock::new(|| {
     Regex::new(r"[-A-Za-z0-9!#$%&'*+/=?^_`{|}~]+(?:\.[-A-Za-z0-9!#$%&'*+/=?^_`{|}~]+)*@(?:[A-Za-z0-9](?:[-A-Za-z0-9]*[A-Za-z0-9])?\.)+[A-Za-z0-9](?:[-A-Za-z0-9]*[A-Za-z0-9])?").unwrap()
 });
 
-// FIXME: This regex doesnt seem to be working
-static USERNAME_REGEX: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"[a-zA-Z0-9.-_]").unwrap());
+static USERNAME_REGEX: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"^[a-z0-9_.-]+$").unwrap());
 
 // Password is expected to be hashed using SHA3-384
 static PASSWORD_REGEX: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"[0-9a-f]{96}").unwrap());