diff --git a/src/main.rs b/src/main.rs
index e05a7c1..3028cc2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -231,14 +231,20 @@ async fn post_item(
 
         writer.flush().await?;
 
+        let now = SystemTime::now().duration_since(UNIX_EPOCH)?.as_secs();
+        let ttl = params.ttl.unwrap_or(24 * 3600);
+        let expires_at = match u64::MAX - ttl > now {
+            true => u64::MAX,
+            false => now + ttl,
+        };
+
         metadata.etag = Some(hex::encode(etag_hasher.finalize()));
         metadata.size = Some(size);
         metadata.content_type = match content_type {
             Some(content_type) => Some(content_type.to_string()),
             None => Some("application/octet-stream".to_string()),
         };
-        metadata.expires_at = SystemTime::now().duration_since(UNIX_EPOCH)?.as_secs()
-            + params.ttl.unwrap_or(24 * 3600);
+        metadata.expires_at = expires_at;
         metadata.to_file(&metadata_path).await?;
 
         app_state