diff --git a/src/contract.rs b/src/contract.rs
index fb22275..e1d9b00 100644
--- a/src/contract.rs
+++ b/src/contract.rs
@@ -132,7 +132,7 @@ pub struct Metadata {
     pub optimization_used: u64,
 
     /// The number of optimizations performed.
-    #[serde(deserialize_with = "deserialize_stringified_u64", alias = "OptimizationRuns")]
+    #[serde(deserialize_with = "deserialize_stringified_u64", alias = "OptimizationRuns", default)]
     pub runs: u64,
 
     /// The constructor arguments the contract was deployed with.