diff --git a/http-api/src/main/java/io/avaje/http/api/PathTypeConversion.java b/http-api/src/main/java/io/avaje/http/api/PathTypeConversion.java
index eff727720..1cd272f20 100644
--- a/http-api/src/main/java/io/avaje/http/api/PathTypeConversion.java
+++ b/http-api/src/main/java/io/avaje/http/api/PathTypeConversion.java
@@ -309,6 +309,20 @@ public static BigDecimal toBigDecimal(String value) {
     }
   }
 
+  /**
+   * Convert to BigInteger (allowing nulls).
+   */
+  public static BigInteger toBigInteger(String value) {
+    if (isNullOrEmpty(value)) {
+      return null;
+    }
+    try {
+      return new BigInteger(value);
+    } catch (Exception e) {
+      throw new InvalidTypeArgumentException(e);
+    }
+  }
+
   /**
    * Convert to Boolean (allowing nulls).
    */