diff --git a/bin/configs/scala-cask-petstore-new.yaml b/bin/configs/scala-cask-petstore.yaml
similarity index 100%
rename from bin/configs/scala-cask-petstore-new.yaml
rename to bin/configs/scala-cask-petstore.yaml
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 5ee43cb4261..e48f46c981f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -3158,7 +3158,7 @@ public class DefaultCodegen implements CodegenConfig {
                 additionalPropertiesIsAnyType = true;
             }
         } else {
-            // if additioanl properties is set (e.g. free form object, any type, string, etc)
+            // if additional properties is set (e.g. free form object, any type, string, etc)
             addPropProp = fromProperty(getAdditionalPropertiesName(), (Schema) schema.getAdditionalProperties(), false);
             additionalPropertiesIsAnyType = true;
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaCaskServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaCaskServerCodegen.java
index c6eae192b9d..e5a56b02fed 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaCaskServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaCaskServerCodegen.java
@@ -39,6 +39,10 @@ import static org.openapitools.codegen.utils.StringUtils.camelize;
 public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements CodegenConfig {
     public static final String PROJECT_NAME = "projectName";
 
+    // this is our opinionated json type - ujson.Value - which is a first-class
+    // citizen of cask
+    private static final String AdditionalPropertiesType = "Value";
+
     private final Logger LOGGER = LoggerFactory.getLogger(ScalaCaskServerCodegen.class);
 
     @Override
@@ -115,6 +119,8 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
 
         typeMapping.put("integer", "Int");
         typeMapping.put("long", "Long");
+        typeMapping.put("AnyType", AdditionalPropertiesType);
+
         //TODO binary should be mapped to byte array
         // mapped to String as a workaround
         typeMapping.put("binary", "String");
@@ -241,6 +247,7 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
         importMapping.put("OffsetDateTime", "java.time.OffsetDateTime");
         importMapping.put("LocalTime", "java.time.LocalTime");
         importMapping.put("Value", "ujson.Value");
+        importMapping.put(AdditionalPropertiesType, "ujson.Value");
     }
 
     static boolean consumesMimetype(CodegenOperation op, String mimetype) {
@@ -614,7 +621,7 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
             if (p.getIsEnumOrRef()) {
                 p.defaultValue = "null";
             } else {
-                p.defaultValue = defaultValueNonOption(p);
+                p.defaultValue = defaultValueNonOption(p, "null");
             }
         } else if (p.defaultValue.contains("Seq.empty")) {
             p.defaultValue = "Nil";
@@ -767,6 +774,23 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
         return defaultValueNonOption(p, fallbackDefaultValue);
     }
 
+    /**
+     * the subtypes of IJsonSchemaValidationProperties have an 'isNumeric', but that's not a method on IJsonSchemaValidationProperties.
+     *
+     * This helper method tries to isolate that noisy logic in a safe way so we can ask 'is this IJsonSchemaValidationProperties numeric'?
+     * @param p the property
+     * @return true if the property is numeric
+     */
+    private static boolean isNumeric(IJsonSchemaValidationProperties p) {
+        if (p instanceof CodegenParameter) {
+            return ((CodegenParameter)p).isNumeric;
+        } else if (p instanceof CodegenProperty) {
+            return ((CodegenProperty)p).isNumeric;
+        } else {
+            return p.getIsNumber() || p.getIsFloat() || p.getIsDecimal() || p.getIsDouble() || p.getIsInteger()  || p.getIsLong() || p.getIsUnboundedInteger();
+        }
+    }
+
     private static String defaultValueNonOption(IJsonSchemaValidationProperties p, String fallbackDefaultValue) {
         if (p.getIsArray()) {
             if (p.getUniqueItems()) {
@@ -777,7 +801,7 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
         if (p.getIsMap()) {
             return "Map.empty";
         }
-        if (p.getIsNumber()) {
+        if (isNumeric(p)) {
             return "0";
         }
         if (p.getIsEnum()) {
@@ -792,38 +816,13 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
         if (p.getIsString()) {
             return "\"\"";
         }
-        return fallbackDefaultValue;
-    }
+        if (fallbackDefaultValue != null && !fallbackDefaultValue.trim().isEmpty()) {
+            return fallbackDefaultValue;
+        }
 
-    private static String defaultValueNonOption(CodegenProperty p) {
-        if (p.getIsArray()) {
-            return "Nil";
-        }
-        if (p.getIsMap()) {
-            return "Map.empty";
-        }
-        if (p.isNumber || p.isNumeric) {
-            return "0";
-        }
-        if (p.isBoolean) {
-            return "false";
-        }
-        if (p.isUuid) {
-            return "java.util.UUID.randomUUID()";
-        }
-        if (p.isModel) {
-            return "null";
-        }
-        if (p.isDate || p.isDateTime) {
-            return "null";
-        }
-        if (p.isString) {
-            return "\"\"";
-        }
-        return p.defaultValue;
+        return "null";
     }
 
-
     @Override
     public CodegenProperty fromProperty(String name, Schema schema) {
         CodegenProperty property = super.fromProperty(name, schema);
@@ -847,9 +846,9 @@ public class ScalaCaskServerCodegen extends AbstractScalaCodegen implements Code
 
     @Override
     public String toModelImport(String name) {
-        final String result = super.toModelImport(name);
+        String result = super.toModelImport(name);
         if (importMapping.containsKey(name)) {
-            return importMapping.get(name);
+            result = importMapping.get(name);
         }
         return result;
     }
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/apiPackage.mustache b/modules/openapi-generator/src/main/resources/scala-cask/apiPackage.mustache
index 6acc47b3100..b315826e170 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/apiPackage.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/apiPackage.mustache
@@ -11,6 +11,7 @@ import java.time.LocalDate
 import java.util.UUID
 import scala.reflect.ClassTag
 import scala.util.*
+import upickle.default.*
 
 // needed for BigDecimal params
 given cask.endpoints.QueryParamReader.SimpleParam[BigDecimal](BigDecimal.apply)
@@ -142,6 +143,15 @@ extension (request: cask.Request) {
   def headerManyValues(paramName: String, required: Boolean): Parsed[List[String]] = Parsed.manyValues(request.headers, paramName, required)
 
   def bodyAsString = new String(request.readAllBytes(), "UTF-8")
+
+  def bodyAsJson : Try[ujson.Value] = {
+      val jason  = bodyAsString
+      try {
+        Success(read[ujson.Value](jason))
+      } catch {
+        case scala.util.control.NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
+      }
+    }
   
   def pathValue(index: Int, paramName: String, required : Boolean): Parsed[String] = {
     request
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/apiRoutes.mustache b/modules/openapi-generator/src/main/resources/scala-cask/apiRoutes.mustache
index db3cdd65cb4..293d74466f1 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/apiRoutes.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/apiRoutes.mustache
@@ -44,7 +44,7 @@ class {{classname}}Routes(service : {{classname}}Service) extends cask.Routes {
 
         val result = {{>parseHttpParams}}
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
         {{#responses}}
             {{#dataType}}
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/exampleApp.mustache b/modules/openapi-generator/src/main/resources/scala-cask/exampleApp.mustache
index f1247210dac..827206a040c 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/exampleApp.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/exampleApp.mustache
@@ -1,6 +1,6 @@
 //> using scala "3.3.1"
-//> using lib "com.lihaoyi::cask:0.9.2"
-//> using lib "com.lihaoyi::scalatags:0.8.2"
+//> using dep "com.lihaoyi::cask:0.9.2"
+//> using dep "com.lihaoyi::scalatags:0.8.2"
 {{>licenseInfo}}
 
 // this file was generated from app.mustache
@@ -11,11 +11,21 @@ package {{packageName}}
 import _root_.{{modelPackage}}.*
 import _root_.{{apiPackage}}.*
 
+/** an example of how you can add your own additional routes to your app */
+object MoreRoutes extends cask.Routes {
+  @cask.get("/echo")
+  def more(request: cask.Request) = s"request was ${request.bodyAsString}"
+
+  initialize()
+}
+
 /**
  * This is an example of how you might extends BaseApp for a runnable application.
  *
  * See the README.md for how to create your own app
  */
 object ExampleApp extends BaseApp() {
+  // override to include our additional route
+  override def allRoutes = super.allRoutes ++ Option(MoreRoutes)
   start()
 }
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/model.mustache b/modules/openapi-generator/src/main/resources/scala-cask/model.mustache
index c4b430b7ced..a6f60a6e9dc 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/model.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/model.mustache
@@ -17,26 +17,28 @@ case class {{classname}}(
 /* {{{description}}} */
   {{/description}}
   {{name}}: {{#isEnum}}{{^required}}Option[{{/required}}{{classname}}.{{datatypeWithEnum}}{{^required}}]{{/required}}{{/isEnum}}{{^isEnum}}{{{vendorExtensions.x-datatype-model}}}{{/isEnum}}{{^required}} = {{{vendorExtensions.x-defaultValue-model}}} {{/required}}{{^-last}},{{/-last}}
+  {{/vars}}
 
-  {{/vars}}) {
+{{#isAdditionalPropertiesTrue}}, additionalProperties : ujson.Value =  ujson.Null{{/isAdditionalPropertiesTrue}}
+) {
 
-  def asJson: String = asData.asJson
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : {{classname}}Data = {
     {{classname}}Data(
         {{#vars}}
             {{name}} = {{name}}{{#vendorExtensions.x-map-asModel}}.map(_.asData){{/vendorExtensions.x-map-asModel}}{{#vendorExtensions.x-wrap-in-optional}}.getOrElse({{{defaultValue}}}){{/vendorExtensions.x-wrap-in-optional}}{{^-last}},{{/-last}}
         {{/vars}}
+        {{#isAdditionalPropertiesTrue}}, additionalProperties{{/isAdditionalPropertiesTrue}}
     )
   }
-
 }
 
-object {{classname}}{
+object {{classname}} {
+    given RW[{{classname}}] = summon[RW[ujson.Value]].bimap[{{classname}}](_.asJson, json => read[{{classname}}Data](json).asModel)
 
-    given RW[{{classname}}] = {{classname}}Data.readWriter.bimap[{{classname}}](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
         {{#vars}}
             case {{name}} extends Fields("{{name}}")
         {{/vars}}
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/modelData.mustache b/modules/openapi-generator/src/main/resources/scala-cask/modelData.mustache
index 8dfdef358f6..ec24792b452 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/modelData.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/modelData.mustache
@@ -21,16 +21,28 @@ case class {{classname}}Data(
 /* {{{description}}} */
   {{/description}}
   {{name}}: {{#isEnum}}{{classname}}.{{datatypeWithEnum}}{{/isEnum}}{{^isEnum}}{{{vendorExtensions.x-datatype-data}}}{{/isEnum}}{{^required}} = {{{vendorExtensions.x-defaultValue-data}}} {{/required}}{{^-last}},{{/-last}}
+  {{/vars}}
+  {{#isAdditionalPropertiesTrue}}, additionalProperties : ujson.Value =  ujson.Null{{/isAdditionalPropertiesTrue}}
 
-  {{/vars}}) {
+) derives RW {
 
-  def asJson: String = write(this)
+  def asJsonString: String = asJson.toString()
+
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    {{#isAdditionalPropertiesTrue}}
+    jason.obj.remove("additionalProperties")
+    jason.mergeWith(additionalProperties)
+    {{/isAdditionalPropertiesTrue}}
+    {{^isAdditionalPropertiesTrue}}
+    jason
+    {{/isAdditionalPropertiesTrue}}
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
     {{#vars}}
-        // ==================
-        // {{name}}
+        // ================== {{name}} validation ==================
         {{#pattern}}
         // validate against pattern '{{{pattern}}}'
         if (errors.isEmpty || !failFast) {
@@ -39,7 +51,6 @@ case class {{classname}}Data(
               errors += ValidationError(path :+ {{classname}}.Fields.{{name}}, s"value '${{name}}' doesn't match pattern $regex")
         }
         {{/pattern}}
-
         {{#minimum}}
         // validate against {{#exclusiveMinimum}}exclusive {{/exclusiveMinimum}}minimum {{minimum}}
         if (errors.isEmpty || !failFast) {
@@ -47,7 +58,6 @@ case class {{classname}}Data(
             errors += ValidationError(path :+ {{classname}}.Fields.{{name}}, s"value '${{name}}' is not greater than the {{#exclusiveMinimum}}exclusive {{/exclusiveMinimum}}minimum value {{minimum}}")
         }
         {{/minimum}}
-
         {{#maximum}}
         // validate against {{#exclusiveMaximum}}exclusive {{/exclusiveMaximum}}maximum {{maximum}}
         if (errors.isEmpty || !failFast) {
@@ -55,7 +65,6 @@ case class {{classname}}Data(
             errors += ValidationError(path :+ {{classname}}.Fields.{{name}}, s"value '${{name}}' is not greater than the {{#exclusiveMaximum}}exclusive {{/exclusiveMaximum}}maximum value {{maximum}}")
         }
         {{/maximum}}
-
         {{#minLength}}
         // validate min length {{minLength}}
         if (errors.isEmpty || !failFast)  {
@@ -65,7 +74,6 @@ case class {{classname}}Data(
             }
         }
         {{/minLength}}
-
         {{#maxLength}}
         // validate max length {{maxLength}}
         if (errors.isEmpty || !failFast)  {
@@ -75,7 +83,6 @@ case class {{classname}}Data(
             }
         }
         {{/maxLength}}
-
         {{#isEmail}}
         // validate {{name}} is a valid email address
         if (errors.isEmpty || !failFast) {
@@ -86,7 +93,6 @@ case class {{classname}}Data(
             }
         }
         {{/isEmail}}
-
         {{#required}}{{^isPrimitiveType}}
         if (errors.isEmpty || !failFast) {
             if ({{name}} == null) {
@@ -94,7 +100,6 @@ case class {{classname}}Data(
             }
         }
         {{/isPrimitiveType}}{{/required}}
-
         {{#uniqueItems}}
           // validate {{name}} has unique items
           if (errors.isEmpty || !failFast) {
@@ -111,7 +116,6 @@ case class {{classname}}Data(
               }
           }
         {{/uniqueItems}}
-
         {{#multipleOf}}
         if (errors.isEmpty || !failFast) {
           // validate {{name}} multiple of {{multipleOf}}
@@ -123,7 +127,6 @@ case class {{classname}}Data(
           }
         }
         {{/multipleOf}}
-
         {{#minItems}}
         // validate min items {{minItems}}
         if (errors.isEmpty || !failFast) {
@@ -133,7 +136,6 @@ case class {{classname}}Data(
             }
         }
         {{/minItems}}
-
         {{#maxItems}}
         // validate min items {{maxItems}}
         if (errors.isEmpty || !failFast) {
@@ -143,15 +145,8 @@ case class {{classname}}Data(
             }
         }
         {{/maxItems}}
-
-        {{#minProperties}}
-           TODO - minProperties
-        {{/minProperties}}
-
-        {{#maxProperties}}
-           TODO - maxProperties
-        {{/maxProperties}}
-
+        {{#minProperties}} TODO - minProperties {{/minProperties}}
+        {{#maxProperties}} TODO - maxProperties {{/maxProperties}}
         {{#items}}{{#isModel}}
         if (errors.isEmpty || !failFast) {
             if ({{name}} != null) {
@@ -192,19 +187,35 @@ case class {{classname}}Data(
         {{#vendorExtensions.x-wrap-in-optional}}){{/vendorExtensions.x-wrap-in-optional}}
         {{#vendorExtensions.x-map-asModel}}.map(_.asModel){{/vendorExtensions.x-map-asModel}}{{^-last}},{{/-last}}
     {{/vars}}
+    {{#isAdditionalPropertiesTrue}}, additionalProperties{{/isAdditionalPropertiesTrue}}
     )
   }
 }
 
 object {{classname}}Data {
 
-  given readWriter : RW[{{classname}}Data] = macroRW
+  def fromJson(jason : ujson.Value) : {{classname}}Data = try {
+        val data = read[{{classname}}Data](jason)
+        {{^isAdditionalPropertiesTrue}}
+        data
+        {{/isAdditionalPropertiesTrue}}
+        {{#isAdditionalPropertiesTrue}}
+        val obj = jason.obj
+        {{classname}}.Fields.values.foreach(v => obj.value.subtractOne(v.fieldName))
+        data.copy(additionalProperties = obj)
+        {{/isAdditionalPropertiesTrue}}
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating {{classname}}Data from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : {{classname}}Data = try {
-        read[{{classname}}Data](jason)
-     } catch {
+  def fromJsonString(jason : String) : {{classname}}Data = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[{{classname}}Data] = try {
         read[List[{{classname}}Data]](jason)
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/modelPackage.mustache b/modules/openapi-generator/src/main/resources/scala-cask/modelPackage.mustache
index f582c3e9fb1..d4928454a90 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/modelPackage.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/modelPackage.mustache
@@ -50,4 +50,21 @@ given ReadWriter[OffsetDateTime] = readwriter[String].bimap[OffsetDateTime](
     str =>  scala.util.Try(OffsetDateTime.parse(str, DateTimeFormatter.ISO_DATE_TIME)).getOrElse(
              OffsetDateTime.parse(str, DateTimeFormatter.ISO_INSTANT)
             )
-)
\ No newline at end of file
+)
+
+
+extension (json: ujson.Value) {
+    def mergeWith(other: ujson.Value): ujson.Value = (json, other) match {
+        case (ujson.Obj(aMap), ujson.Obj(bMap)) =>
+            val mergedMap: scala.collection.mutable.Map[String, ujson.Value] = aMap ++ bMap.map {
+                case (k, v) => k -> (aMap.get(k) match {
+                                        case Some(aValue) => aValue.mergeWith(v)
+                                        case None         => v
+                                    })
+            }
+            ujson.Obj.from(mergedMap)
+        case (ujson.Arr(aArray), ujson.Arr(bArray)) => ujson.Arr(aArray ++ bArray)
+        case (aValue, ujson.Null) => aValue
+        case (_, bValue)          => bValue
+    }
+}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/openapiRoute.mustache b/modules/openapi-generator/src/main/resources/scala-cask/openapiRoute.mustache
index 58c35063555..0656d1e4600 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/openapiRoute.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/openapiRoute.mustache
@@ -63,7 +63,7 @@ class OpenApiRoutes(localPort: Int, swaggerUrl: Option[String]) extends cask.Rou
       val urlConn = new URL(url).openConnection()
       urlConn.setRequestProperty("User-Agent", "Mozilla/5.0")
 
-      Using(urlConn.getInputStream) { inputStream =>
+      val extracted = Using(urlConn.getInputStream) { inputStream =>
         val zipIn = new ZipInputStream(new BufferedInputStream(inputStream))
         LazyList.continually(zipIn.getNextEntry).takeWhile(_ != null).foreach { entry =>
 
@@ -77,6 +77,12 @@ class OpenApiRoutes(localPort: Int, swaggerUrl: Option[String]) extends cask.Rou
           zipIn.closeEntry()
         }
       }
+
+      if  (extracted.isFailure) {
+        println(s"Error extracting swagger: ${extracted}")
+      } else {
+        println(s"Extracting swagger: ${extracted}")
+      }
     }
 
     def extractFile(name: String, zipIn: ZipInputStream, filePath: String): Unit = {
diff --git a/modules/openapi-generator/src/main/resources/scala-cask/parseHttpParams.mustache b/modules/openapi-generator/src/main/resources/scala-cask/parseHttpParams.mustache
index 18193e0606c..6da75c69786 100644
--- a/modules/openapi-generator/src/main/resources/scala-cask/parseHttpParams.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-cask/parseHttpParams.mustache
@@ -38,7 +38,8 @@
             {{/vendorExtensions.x-deserialize-asModelMap}}
           {{/isMap}}
           {{^isMap}}
-              {{paramName}}Data <- Parsed.eval({{vendorExtensions.x-container-type}}Data.fromJsonString(request.bodyAsString)).mapError(e => s"Error parsing json as {{vendorExtensions.x-container-type}} from >${request.bodyAsString}< : ${e}") /* not array or map */
+              {{paramName}}Json <- Parsed.fromTry(request.bodyAsJson)
+              {{paramName}}Data <- Parsed.eval({{vendorExtensions.x-container-type}}Data.fromJson({{paramName}}Json)) /* not array or map */
               {{paramName}} <- Parsed.fromTry({{paramName}}Data.validated(failFast))
           {{/isMap}}
         {{/isArray}}
diff --git a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/ExampleApp.scala b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/ExampleApp.scala
index 9c5e733b73e..b49381daf7e 100644
--- a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/ExampleApp.scala
+++ b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/ExampleApp.scala
@@ -1,6 +1,6 @@
 //> using scala "3.3.1"
-//> using lib "com.lihaoyi::cask:0.9.2"
-//> using lib "com.lihaoyi::scalatags:0.8.2"
+//> using dep "com.lihaoyi::cask:0.9.2"
+//> using dep "com.lihaoyi::scalatags:0.8.2"
 /**
  * OpenAPI Petstore
  * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
@@ -21,11 +21,21 @@ package cask.groupId.server
 import _root_.sample.cask.model.*
 import _root_.sample.cask.api.*
 
+/** an example of how you can add your own additional routes to your app */
+object MoreRoutes extends cask.Routes {
+  @cask.get("/echo")
+  def more(request: cask.Request) = s"request was ${request.bodyAsString}"
+
+  initialize()
+}
+
 /**
  * This is an example of how you might extends BaseApp for a runnable application.
  *
  * See the README.md for how to create your own app
  */
 object ExampleApp extends BaseApp() {
+  // override to include our additional route
+  override def allRoutes = super.allRoutes ++ Option(MoreRoutes)
   start()
 }
diff --git a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/OpenApiRoutes.scala b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/OpenApiRoutes.scala
index a991ce2aaf4..403a519f2a3 100644
--- a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/OpenApiRoutes.scala
+++ b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/OpenApiRoutes.scala
@@ -75,7 +75,7 @@ class OpenApiRoutes(localPort: Int, swaggerUrl: Option[String]) extends cask.Rou
       val urlConn = new URL(url).openConnection()
       urlConn.setRequestProperty("User-Agent", "Mozilla/5.0")
 
-      Using(urlConn.getInputStream) { inputStream =>
+      val extracted = Using(urlConn.getInputStream) { inputStream =>
         val zipIn = new ZipInputStream(new BufferedInputStream(inputStream))
         LazyList.continually(zipIn.getNextEntry).takeWhile(_ != null).foreach { entry =>
 
@@ -89,6 +89,12 @@ class OpenApiRoutes(localPort: Int, swaggerUrl: Option[String]) extends cask.Rou
           zipIn.closeEntry()
         }
       }
+
+      if  (extracted.isFailure) {
+        println(s"Error extracting swagger: ${extracted}")
+      } else {
+        println(s"Extracting swagger: ${extracted}")
+      }
     }
 
     def extractFile(name: String, zipIn: ZipInputStream, filePath: String): Unit = {
diff --git a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/PetRoutes.scala b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/PetRoutes.scala
index 75d4799d6e3..e69ef16de01 100644
--- a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/PetRoutes.scala
+++ b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/PetRoutes.scala
@@ -60,12 +60,13 @@ class PetRoutes(service : PetService) extends cask.Routes {
         def failFast = request.queryParams.keySet.contains("failFast")
 
         val result =         for {
-              petData <- Parsed.eval(PetData.fromJsonString(request.bodyAsString)).mapError(e => s"Error parsing json as Pet from >${request.bodyAsString}< : ${e}") /* not array or map */
+              petJson <- Parsed.fromTry(request.bodyAsJson)
+              petData <- Parsed.eval(PetData.fromJson(petJson)) /* not array or map */
               pet <- Parsed.fromTry(petData.validated(failFast))
             result <- Parsed.eval(service.addPet(pet))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : Pet) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -86,7 +87,7 @@ class PetRoutes(service : PetService) extends cask.Routes {
             result <- Parsed.eval(service.deletePet(petId, apiKey))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -104,7 +105,7 @@ class PetRoutes(service : PetService) extends cask.Routes {
             result <- Parsed.eval(service.findPetsByStatus(status))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : List[Pet]) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -123,7 +124,7 @@ class PetRoutes(service : PetService) extends cask.Routes {
             result <- Parsed.eval(service.findPetsByTags(tags))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : List[Pet]) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -143,7 +144,7 @@ class PetRoutes(service : PetService) extends cask.Routes {
             result <- Parsed.eval(service.getPetById(petId))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : Pet) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -159,12 +160,13 @@ class PetRoutes(service : PetService) extends cask.Routes {
         def failFast = request.queryParams.keySet.contains("failFast")
 
         val result =         for {
-              petData <- Parsed.eval(PetData.fromJsonString(request.bodyAsString)).mapError(e => s"Error parsing json as Pet from >${request.bodyAsString}< : ${e}") /* not array or map */
+              petJson <- Parsed.fromTry(request.bodyAsJson)
+              petData <- Parsed.eval(PetData.fromJson(petJson)) /* not array or map */
               pet <- Parsed.fromTry(petData.validated(failFast))
             result <- Parsed.eval(service.updatePet(pet))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : Pet) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -186,7 +188,7 @@ class PetRoutes(service : PetService) extends cask.Routes {
             result <- Parsed.eval(service.updatePetWithForm(petId, name, status))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -207,7 +209,7 @@ class PetRoutes(service : PetService) extends cask.Routes {
             result <- Parsed.eval(service.uploadFile(petId, additionalMetadata, file))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : ApiResponse) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
diff --git a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/StoreRoutes.scala b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/StoreRoutes.scala
index ede98a18d8b..b4a550889d7 100644
--- a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/StoreRoutes.scala
+++ b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/StoreRoutes.scala
@@ -41,7 +41,7 @@ class StoreRoutes(service : StoreService) extends cask.Routes {
             result <- Parsed.eval(service.deleteOrder(orderId))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -59,7 +59,7 @@ class StoreRoutes(service : StoreService) extends cask.Routes {
             result <- Parsed.eval(service.getInventory())
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : Map[String, Int]) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -78,7 +78,7 @@ class StoreRoutes(service : StoreService) extends cask.Routes {
             result <- Parsed.eval(service.getOrderById(orderId))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : Order) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -93,12 +93,13 @@ class StoreRoutes(service : StoreService) extends cask.Routes {
         def failFast = request.queryParams.keySet.contains("failFast")
 
         val result =         for {
-              orderData <- Parsed.eval(OrderData.fromJsonString(request.bodyAsString)).mapError(e => s"Error parsing json as Order from >${request.bodyAsString}< : ${e}") /* not array or map */
+              orderJson <- Parsed.fromTry(request.bodyAsJson)
+              orderData <- Parsed.eval(OrderData.fromJson(orderJson)) /* not array or map */
               order <- Parsed.fromTry(orderData.validated(failFast))
             result <- Parsed.eval(service.placeOrder(order))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : Order) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
diff --git a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/UserRoutes.scala b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/UserRoutes.scala
index 3bd483d6b80..64b82a45d88 100644
--- a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/UserRoutes.scala
+++ b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/UserRoutes.scala
@@ -49,12 +49,13 @@ class UserRoutes(service : UserService) extends cask.Routes {
         def failFast = request.queryParams.keySet.contains("failFast")
 
         val result =         for {
-              userData <- Parsed.eval(UserData.fromJsonString(request.bodyAsString)).mapError(e => s"Error parsing json as User from >${request.bodyAsString}< : ${e}") /* not array or map */
+              userJson <- Parsed.fromTry(request.bodyAsJson)
+              userData <- Parsed.eval(UserData.fromJson(userJson)) /* not array or map */
               user <- Parsed.fromTry(userData.validated(failFast))
             result <- Parsed.eval(service.createUser(user))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -73,7 +74,7 @@ class UserRoutes(service : UserService) extends cask.Routes {
             result <- Parsed.eval(service.createUsersWithArrayInput(user))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -92,7 +93,7 @@ class UserRoutes(service : UserService) extends cask.Routes {
             result <- Parsed.eval(service.createUsersWithListInput(user))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -111,7 +112,7 @@ class UserRoutes(service : UserService) extends cask.Routes {
             result <- Parsed.eval(service.deleteUser(username))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -129,7 +130,7 @@ class UserRoutes(service : UserService) extends cask.Routes {
             result <- Parsed.eval(service.getUserByName(username))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : User) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -147,7 +148,7 @@ class UserRoutes(service : UserService) extends cask.Routes {
             result <- Parsed.eval(service.loginUser(username, password))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(value : String) => cask.Response(data = write(value), 200, headers = Seq("Content-Type" -> "application/json"))
           case Right(other) => cask.Response(s"$other", 200)
@@ -166,7 +167,7 @@ class UserRoutes(service : UserService) extends cask.Routes {
             result <- Parsed.eval(service.logoutUser())
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
@@ -182,12 +183,13 @@ class UserRoutes(service : UserService) extends cask.Routes {
 
         val result =         for {
             username <- Parsed(username)
-              userData <- Parsed.eval(UserData.fromJsonString(request.bodyAsString)).mapError(e => s"Error parsing json as User from >${request.bodyAsString}< : ${e}") /* not array or map */
+              userJson <- Parsed.fromTry(request.bodyAsJson)
+              userData <- Parsed.eval(UserData.fromJson(userJson)) /* not array or map */
               user <- Parsed.fromTry(userData.validated(failFast))
             result <- Parsed.eval(service.updateUser(username, user))
         } yield result
 
-        result match {
+        (result : @unchecked) match {
           case Left(error) => cask.Response(error, 500)
           case Right(other) => cask.Response(s"$other", 200)
         }
diff --git a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/package.scala b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/package.scala
index ab25a84875a..10b838f37aa 100644
--- a/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/package.scala
+++ b/samples/server/petstore/scala-cask/jvm/src/main/scala/sample/cask/api/package.scala
@@ -23,6 +23,7 @@ import java.time.LocalDate
 import java.util.UUID
 import scala.reflect.ClassTag
 import scala.util.*
+import upickle.default.*
 
 // needed for BigDecimal params
 given cask.endpoints.QueryParamReader.SimpleParam[BigDecimal](BigDecimal.apply)
@@ -154,6 +155,15 @@ extension (request: cask.Request) {
   def headerManyValues(paramName: String, required: Boolean): Parsed[List[String]] = Parsed.manyValues(request.headers, paramName, required)
 
   def bodyAsString = new String(request.readAllBytes(), "UTF-8")
+
+  def bodyAsJson : Try[ujson.Value] = {
+      val jason  = bodyAsString
+      try {
+        Success(read[ujson.Value](jason))
+      } catch {
+        case scala.util.control.NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
+      }
+    }
   
   def pathValue(index: Int, paramName: String, required : Boolean): Parsed[String] = {
     request
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponse.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponse.scala
index ff5d8abaa14..4fb7f930c58 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponse.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponse.scala
@@ -21,30 +21,29 @@ import upickle.default.*
 
 case class ApiResponse(
   code: Option[Int] = None ,
+  `type`: Option[String] = None ,
+  message: Option[String] = None 
 
-    `type`: Option[String] = None ,
 
-    message: Option[String] = None 
+) {
 
-  ) {
-
-  def asJson: String = asData.asJson
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : ApiResponseData = {
     ApiResponseData(
             code = code.getOrElse(0),
             `type` = `type`.getOrElse(""),
             message = message.getOrElse("")
+        
     )
   }
-
 }
 
-object ApiResponse{
+object ApiResponse {
+    given RW[ApiResponse] = summon[RW[ujson.Value]].bimap[ApiResponse](_.asJson, json => read[ApiResponseData](json).asModel)
 
-    given RW[ApiResponse] = ApiResponseData.readWriter.bimap[ApiResponse](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
             case code extends Fields("code")
             case `type` extends Fields("`type`")
             case message extends Fields("message")
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponseData.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponseData.scala
index b93b7eb44ef..9212af8a3df 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponseData.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/ApiResponseData.scala
@@ -25,69 +25,37 @@ import upickle.default.*
   */
 case class ApiResponseData(
   code: Int = 0 ,
+  `type`: String = "" ,
+  message: String = "" 
+  
 
-    `type`: String = "" ,
+) derives RW {
 
-    message: String = "" 
+  def asJsonString: String = asJson.toString()
 
-  ) {
-
-  def asJson: String = write(this)
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    jason
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
-        // ==================
-        // code
-
-
-
-
-
-
+        // ================== code validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== `type` validation ==================
+        
+        
+        
         
 
-        // ==================
-        // `type`
-
-
-
-
-
-
+        // ================== message validation ==================
         
-
-
-
-
-
-
-
         
-
-        // ==================
-        // message
-
-
-
-
-
-
         
-
-
-
-
-
-
-
         
 
     errors.toSeq
@@ -115,19 +83,28 @@ case class ApiResponseData(
         message
         )
         
+    
     )
   }
 }
 
 object ApiResponseData {
 
-  given readWriter : RW[ApiResponseData] = macroRW
+  def fromJson(jason : ujson.Value) : ApiResponseData = try {
+        val data = read[ApiResponseData](jason)
+        data
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating ApiResponseData from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : ApiResponseData = try {
-        read[ApiResponseData](jason)
-     } catch {
+  def fromJsonString(jason : String) : ApiResponseData = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[ApiResponseData] = try {
         read[List[ApiResponseData]](jason)
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Category.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Category.scala
index d0bf01a2861..b143171f9d2 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Category.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Category.scala
@@ -21,27 +21,27 @@ import upickle.default.*
 
 case class Category(
   id: Option[Long] = None ,
+  name: Option[String] = None 
 
-    name: Option[String] = None 
 
-  ) {
+) {
 
-  def asJson: String = asData.asJson
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : CategoryData = {
     CategoryData(
             id = id.getOrElse(0),
             name = name.getOrElse("")
+        
     )
   }
-
 }
 
-object Category{
+object Category {
+    given RW[Category] = summon[RW[ujson.Value]].bimap[Category](_.asJson, json => read[CategoryData](json).asModel)
 
-    given RW[Category] = CategoryData.readWriter.bimap[Category](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
             case id extends Fields("id")
             case name extends Fields("name")
     }
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/CategoryData.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/CategoryData.scala
index 77a834683a8..5c0dcdfc4cc 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/CategoryData.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/CategoryData.scala
@@ -25,55 +25,36 @@ import upickle.default.*
   */
 case class CategoryData(
   id: Long = 0 ,
+  name: String = "" 
+  
 
-    name: String = "" 
+) derives RW {
 
-  ) {
+  def asJsonString: String = asJson.toString()
 
-  def asJson: String = write(this)
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    jason
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
-        // ==================
-        // id
-
-
-
-
-
-
+        // ================== id validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
-        
-
-        // ==================
-        // name
+        // ================== name validation ==================
         // validate against pattern '^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$'
         if (errors.isEmpty || !failFast) {
            val regex = """^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$"""
            if name == null || !regex.r.matches(name) then
               errors += ValidationError(path :+ Category.Fields.name, s"value '$name' doesn't match pattern $regex")
         }
-
-
-
-
-
-
         
-
-
-
-
-
-
-
+        
+        
         
 
     errors.toSeq
@@ -97,19 +78,28 @@ case class CategoryData(
         name
         )
         
+    
     )
   }
 }
 
 object CategoryData {
 
-  given readWriter : RW[CategoryData] = macroRW
+  def fromJson(jason : ujson.Value) : CategoryData = try {
+        val data = read[CategoryData](jason)
+        data
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating CategoryData from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : CategoryData = try {
-        read[CategoryData](jason)
-     } catch {
+  def fromJsonString(jason : String) : CategoryData = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[CategoryData] = try {
         read[List[CategoryData]](jason)
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Order.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Order.scala
index 85bda97b815..354e8a5e752 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Order.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Order.scala
@@ -22,21 +22,18 @@ import upickle.default.*
 
 case class Order(
   id: Option[Long] = None ,
-
-    petId: Option[Long] = None ,
-
-    quantity: Option[Int] = None ,
-
-    shipDate: Option[OffsetDateTime] = None ,
-
-  /* Order Status */
+  petId: Option[Long] = None ,
+  quantity: Option[Int] = None ,
+  shipDate: Option[OffsetDateTime] = None ,
+/* Order Status */
   status: Option[Order.StatusEnum] = None ,
+  complete: Option[Boolean] = None 
 
-    complete: Option[Boolean] = None 
 
-  ) {
+) {
 
-  def asJson: String = asData.asJson
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : OrderData = {
     OrderData(
@@ -46,16 +43,15 @@ case class Order(
             shipDate = shipDate.getOrElse(null),
             status = status.getOrElse(null),
             complete = complete.getOrElse(false)
+        
     )
   }
-
 }
 
-object Order{
+object Order {
+    given RW[Order] = summon[RW[ujson.Value]].bimap[Order](_.asJson, json => read[OrderData](json).asModel)
 
-    given RW[Order] = OrderData.readWriter.bimap[Order](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
             case id extends Fields("id")
             case petId extends Fields("petId")
             case quantity extends Fields("quantity")
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/OrderData.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/OrderData.scala
index 0de58a7f0b3..16d81bce47a 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/OrderData.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/OrderData.scala
@@ -26,130 +26,59 @@ import upickle.default.*
   */
 case class OrderData(
   id: Long = 0 ,
-
-    petId: Long = 0 ,
-
-    quantity: Int = 0 ,
-
-    shipDate: OffsetDateTime = null ,
-
-  /* Order Status */
+  petId: Long = 0 ,
+  quantity: Int = 0 ,
+  shipDate: OffsetDateTime = null ,
+/* Order Status */
   status: Order.StatusEnum = null ,
+  complete: Boolean = false 
+  
 
-    complete: Boolean = false 
+) derives RW {
 
-  ) {
+  def asJsonString: String = asJson.toString()
 
-  def asJson: String = write(this)
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    jason
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
-        // ==================
-        // id
-
-
-
-
-
-
+        // ================== id validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== petId validation ==================
+        
+        
+        
         
 
-        // ==================
-        // petId
-
-
-
-
-
-
+        // ================== quantity validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== shipDate validation ==================
+        
+        
+        
         
 
-        // ==================
-        // quantity
-
-
-
-
-
-
+        // ================== status validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== complete validation ==================
         
-
-        // ==================
-        // shipDate
-
-
-
-
-
-
         
-
-
-
-
-
-
-
         
-
-        // ==================
-        // status
-
-
-
-
-
-
-        
-
-
-
-
-
-
-
-        
-
-        // ==================
-        // complete
-
-
-
-
-
-
-        
-
-
-
-
-
-
-
         
 
     errors.toSeq
@@ -189,19 +118,28 @@ case class OrderData(
         complete
         )
         
+    
     )
   }
 }
 
 object OrderData {
 
-  given readWriter : RW[OrderData] = macroRW
+  def fromJson(jason : ujson.Value) : OrderData = try {
+        val data = read[OrderData](jason)
+        data
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating OrderData from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : OrderData = try {
-        read[OrderData](jason)
-     } catch {
+  def fromJsonString(jason : String) : OrderData = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[OrderData] = try {
         read[List[OrderData]](jason)
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Pet.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Pet.scala
index 068f593303c..44c16221842 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Pet.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Pet.scala
@@ -23,21 +23,18 @@ import upickle.default.*
 
 case class Pet(
   id: Option[Long] = None ,
-
-    category: Option[Category] = None ,
-
-    name: String,
-
-    photoUrls: Seq[String],
-
-    tags: Seq[Tag] = Nil ,
-
-  /* pet status in the store */
+  category: Option[Category] = None ,
+  name: String,
+  photoUrls: Seq[String],
+  tags: Seq[Tag] = Nil ,
+/* pet status in the store */
   status: Option[Pet.StatusEnum] = None 
 
-  ) {
 
-  def asJson: String = asData.asJson
+) {
+
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : PetData = {
     PetData(
@@ -47,16 +44,15 @@ case class Pet(
             photoUrls = photoUrls,
             tags = tags.map(_.asData),
             status = status.getOrElse(null)
+        
     )
   }
-
 }
 
-object Pet{
+object Pet {
+    given RW[Pet] = summon[RW[ujson.Value]].bimap[Pet](_.asJson, json => read[PetData](json).asModel)
 
-    given RW[Pet] = PetData.readWriter.bimap[Pet](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
             case id extends Fields("id")
             case category extends Fields("category")
             case name extends Fields("name")
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/PetData.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/PetData.scala
index db6a3e1a512..ea7a34c6193 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/PetData.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/PetData.scala
@@ -27,116 +27,57 @@ import upickle.default.*
   */
 case class PetData(
   id: Long = 0 ,
-
-    category: CategoryData = null ,
-
-    name: String,
-
-    photoUrls: Seq[String],
-
-    tags: Seq[TagData] = Nil ,
-
-  /* pet status in the store */
+  category: CategoryData = null ,
+  name: String,
+  photoUrls: Seq[String],
+  tags: Seq[TagData] = Nil ,
+/* pet status in the store */
   status: Pet.StatusEnum = null 
+  
 
-  ) {
+) derives RW {
 
-  def asJson: String = write(this)
+  def asJsonString: String = asJson.toString()
+
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    jason
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
-        // ==================
-        // id
-
-
-
-
-
-
+        // ================== id validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== category validation ==================
+        
         
-
-        // ==================
-        // category
-
-
-
-
-
-
         
-
-
-
-
-
-
-
         
         // validating category
         if (errors.isEmpty || !failFast) {
             if category != null then errors ++= category.validationErrors(path :+ Pet.Fields.category, failFast)
         }
 
-        // ==================
-        // name
-
-
-
-
-
-
+        // ================== name validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== photoUrls validation ==================
+        
+        
+        
         
 
-        // ==================
-        // photoUrls
-
-
-
-
-
-
+        // ================== tags validation ==================
         
-
-
-
-
-
-
-
         
-
-        // ==================
-        // tags
-
-
-
-
-
-
         
-
-
-
-
-
-
-
         
         if (errors.isEmpty || !failFast) {
             if (tags != null) {
@@ -151,22 +92,10 @@ case class PetData(
         }
         
 
-        // ==================
-        // status
-
-
-
-
-
-
+        // ================== status validation ==================
+        
+        
         
-
-
-
-
-
-
-
         
 
     errors.toSeq
@@ -206,19 +135,28 @@ case class PetData(
         status
         )
         
+    
     )
   }
 }
 
 object PetData {
 
-  given readWriter : RW[PetData] = macroRW
+  def fromJson(jason : ujson.Value) : PetData = try {
+        val data = read[PetData](jason)
+        data
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating PetData from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : PetData = try {
-        read[PetData](jason)
-     } catch {
+  def fromJsonString(jason : String) : PetData = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[PetData] = try {
         read[List[PetData]](jason)
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Tag.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Tag.scala
index a8bd2a35866..0406c84c56c 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Tag.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/Tag.scala
@@ -21,27 +21,27 @@ import upickle.default.*
 
 case class Tag(
   id: Option[Long] = None ,
+  name: Option[String] = None 
 
-    name: Option[String] = None 
 
-  ) {
+) {
 
-  def asJson: String = asData.asJson
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : TagData = {
     TagData(
             id = id.getOrElse(0),
             name = name.getOrElse("")
+        
     )
   }
-
 }
 
-object Tag{
+object Tag {
+    given RW[Tag] = summon[RW[ujson.Value]].bimap[Tag](_.asJson, json => read[TagData](json).asModel)
 
-    given RW[Tag] = TagData.readWriter.bimap[Tag](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
             case id extends Fields("id")
             case name extends Fields("name")
     }
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/TagData.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/TagData.scala
index e8c66334bcb..e6aa8c81642 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/TagData.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/TagData.scala
@@ -25,49 +25,30 @@ import upickle.default.*
   */
 case class TagData(
   id: Long = 0 ,
+  name: String = "" 
+  
 
-    name: String = "" 
+) derives RW {
 
-  ) {
+  def asJsonString: String = asJson.toString()
 
-  def asJson: String = write(this)
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    jason
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
-        // ==================
-        // id
-
-
-
-
-
-
+        // ================== id validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== name validation ==================
+        
         
-
-        // ==================
-        // name
-
-
-
-
-
-
         
-
-
-
-
-
-
-
         
 
     errors.toSeq
@@ -91,19 +72,28 @@ case class TagData(
         name
         )
         
+    
     )
   }
 }
 
 object TagData {
 
-  given readWriter : RW[TagData] = macroRW
+  def fromJson(jason : ujson.Value) : TagData = try {
+        val data = read[TagData](jason)
+        data
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating TagData from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : TagData = try {
-        read[TagData](jason)
-     } catch {
+  def fromJsonString(jason : String) : TagData = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[TagData] = try {
         read[List[TagData]](jason)
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/User.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/User.scala
index 286cdb3b652..5dfb0761b78 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/User.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/User.scala
@@ -21,25 +21,20 @@ import upickle.default.*
 
 case class User(
   id: Option[Long] = None ,
-
-    username: Option[String] = None ,
-
-    firstName: Option[String] = None ,
-
-    lastName: Option[String] = None ,
-
-    email: Option[String] = None ,
-
-    password: Option[String] = None ,
-
-    phone: Option[String] = None ,
-
-  /* User Status */
+  username: Option[String] = None ,
+  firstName: Option[String] = None ,
+  lastName: Option[String] = None ,
+  email: Option[String] = None ,
+  password: Option[String] = None ,
+  phone: Option[String] = None ,
+/* User Status */
   userStatus: Option[Int] = None 
 
-  ) {
 
-  def asJson: String = asData.asJson
+) {
+
+  def asJsonString: String = asData.asJsonString
+  def asJson: ujson.Value = asData.asJson
 
   def asData : UserData = {
     UserData(
@@ -51,16 +46,15 @@ case class User(
             password = password.getOrElse(""),
             phone = phone.getOrElse(""),
             userStatus = userStatus.getOrElse(0)
+        
     )
   }
-
 }
 
-object User{
+object User {
+    given RW[User] = summon[RW[ujson.Value]].bimap[User](_.asJson, json => read[UserData](json).asModel)
 
-    given RW[User] = UserData.readWriter.bimap[User](_.asData, _.asModel)
-
-    enum Fields(fieldName : String) extends Field(fieldName) {
+    enum Fields(val fieldName : String) extends Field(fieldName) {
             case id extends Fields("id")
             case username extends Fields("username")
             case firstName extends Fields("firstName")
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/UserData.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/UserData.scala
index 8b8ca7908ab..42cd2a14f83 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/UserData.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/UserData.scala
@@ -25,170 +25,73 @@ import upickle.default.*
   */
 case class UserData(
   id: Long = 0 ,
-
-    username: String = "" ,
-
-    firstName: String = "" ,
-
-    lastName: String = "" ,
-
-    email: String = "" ,
-
-    password: String = "" ,
-
-    phone: String = "" ,
-
-  /* User Status */
+  username: String = "" ,
+  firstName: String = "" ,
+  lastName: String = "" ,
+  email: String = "" ,
+  password: String = "" ,
+  phone: String = "" ,
+/* User Status */
   userStatus: Int = 0 
+  
 
-  ) {
+) derives RW {
 
-  def asJson: String = write(this)
+  def asJsonString: String = asJson.toString()
+
+  def asJson : ujson.Value = {
+    val jason = writeJs(this)
+    jason
+  }
 
   def validationErrors(path : Seq[Field], failFast : Boolean) : Seq[ValidationError] = {
     val errors = scala.collection.mutable.ListBuffer[ValidationError]()
-        // ==================
-        // id
-
-
-
-
-
-
+        // ================== id validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== username validation ==================
+        
+        
+        
         
 
-        // ==================
-        // username
-
-
-
-
-
-
+        // ================== firstName validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== lastName validation ==================
+        
+        
+        
         
 
-        // ==================
-        // firstName
-
-
-
-
-
-
+        // ================== email validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== password validation ==================
+        
+        
+        
         
 
-        // ==================
-        // lastName
-
-
-
-
-
-
+        // ================== phone validation ==================
+        
+        
+        
         
 
-
-
-
-
-
-
+        // ================== userStatus validation ==================
         
-
-        // ==================
-        // email
-
-
-
-
-
-
         
-
-
-
-
-
-
-
         
-
-        // ==================
-        // password
-
-
-
-
-
-
-        
-
-
-
-
-
-
-
-        
-
-        // ==================
-        // phone
-
-
-
-
-
-
-        
-
-
-
-
-
-
-
-        
-
-        // ==================
-        // userStatus
-
-
-
-
-
-
-        
-
-
-
-
-
-
-
         
 
     errors.toSeq
@@ -236,19 +139,28 @@ case class UserData(
         userStatus
         )
         
+    
     )
   }
 }
 
 object UserData {
 
-  given readWriter : RW[UserData] = macroRW
+  def fromJson(jason : ujson.Value) : UserData = try {
+        val data = read[UserData](jason)
+        data
+    } catch {
+      case NonFatal(e) => sys.error(s"Error creating UserData from json '$jason': $e")
+  }
 
-  def fromJsonString(jason : String) : UserData = try {
-        read[UserData](jason)
-     } catch {
+  def fromJsonString(jason : String) : UserData = {
+        val parsed = try {
+           read[ujson.Value](jason)
+        } catch {
           case NonFatal(e) => sys.error(s"Error parsing json '$jason': $e")
-     }
+        }
+        fromJson(parsed)
+  }
 
   def manyFromJsonString(jason : String) : Seq[UserData] = try {
         read[List[UserData]](jason)
diff --git a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/package.scala b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/package.scala
index b0c893da671..45a650c9fb6 100644
--- a/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/package.scala
+++ b/samples/server/petstore/scala-cask/shared/src/main/scala/sample/cask/model/package.scala
@@ -62,4 +62,21 @@ given ReadWriter[OffsetDateTime] = readwriter[String].bimap[OffsetDateTime](
     str =>  scala.util.Try(OffsetDateTime.parse(str, DateTimeFormatter.ISO_DATE_TIME)).getOrElse(
              OffsetDateTime.parse(str, DateTimeFormatter.ISO_INSTANT)
             )
-)
\ No newline at end of file
+)
+
+
+extension (json: ujson.Value) {
+    def mergeWith(other: ujson.Value): ujson.Value = (json, other) match {
+        case (ujson.Obj(aMap), ujson.Obj(bMap)) =>
+            val mergedMap: scala.collection.mutable.Map[String, ujson.Value] = aMap ++ bMap.map {
+                case (k, v) => k -> (aMap.get(k) match {
+                                        case Some(aValue) => aValue.mergeWith(v)
+                                        case None         => v
+                                    })
+            }
+            ujson.Obj.from(mergedMap)
+        case (ujson.Arr(aArray), ujson.Arr(bArray)) => ujson.Arr(aArray ++ bArray)
+        case (aValue, ujson.Null) => aValue
+        case (_, bValue)          => bValue
+    }
+}
\ No newline at end of file