diff --git a/router/src/validation.rs b/router/src/validation.rs
index 268c9c7a..4a9d0c23 100644
--- a/router/src/validation.rs
+++ b/router/src/validation.rs
@@ -6,7 +6,7 @@ use thiserror::Error;
 use tokenizers::tokenizer::Tokenizer;
 use tokio::sync::{mpsc, oneshot};
 
-const MAX_MAX_NEW_TOKENS: usize = 512;
+const MAX_MAX_NEW_TOKENS: u32 = 512;
 const MAX_STOP_SEQUENCES: usize = 4;
 
 /// Validation
@@ -112,7 +112,7 @@ fn validate(
     if request.parameters.top_k < 0 {
         return Err(ValidationError::TopK);
     }
-    if request.parameters.max_new_tokens as usize > MAX_MAX_NEW_TOKENS {
+    if request.parameters.max_new_tokens > MAX_MAX_NEW_TOKENS {
         return Err(ValidationError::MaxNewTokens(MAX_MAX_NEW_TOKENS));
     }
     if request.parameters.stop.len() > MAX_STOP_SEQUENCES {
@@ -153,7 +153,7 @@ pub enum ValidationError {
     #[error("top_k must be strictly positive")]
     TopK,
     #[error("max_new_tokens must be <= {0}")]
-    MaxNewTokens(usize),
+    MaxNewTokens(u32),
     #[error("inputs must have less than {1} tokens. Given: {0}")]
     InputLength(usize, usize),
     #[error("stop supports up to {0} stop sequences. Given: {1}")]