diff --git a/annotations/src/main/kotlin/io/github/tabilzad/ktor/annotations/Annotations.kt b/annotations/src/main/kotlin/io/github/tabilzad/ktor/annotations/Annotations.kt
index 2fb39b6..e48e55e 100644
--- a/annotations/src/main/kotlin/io/github/tabilzad/ktor/annotations/Annotations.kt
+++ b/annotations/src/main/kotlin/io/github/tabilzad/ktor/annotations/Annotations.kt
@@ -47,3 +47,10 @@ annotation class KtorFieldDescription(
     val description: String = "",
     val required: Boolean = false
 )
+
+@Retention(AnnotationRetention.SOURCE)
+@Target(AnnotationTarget.FIELD)
+annotation class OpenApiProperty(
+    val type : String = "",
+    val format: String = ""
+)
diff --git a/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/k2/visitors/ClassDescriptorVisitorK2.kt b/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/k2/visitors/ClassDescriptorVisitorK2.kt
index 4bc7591..17dfb73 100644
--- a/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/k2/visitors/ClassDescriptorVisitorK2.kt
+++ b/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/k2/visitors/ClassDescriptorVisitorK2.kt
@@ -3,6 +3,7 @@ package io.github.tabilzad.ktor.k2.visitors
 import io.github.tabilzad.ktor.PluginConfiguration
 import io.github.tabilzad.ktor.annotations.KtorDescription
 import io.github.tabilzad.ktor.annotations.KtorFieldDescription
+import io.github.tabilzad.ktor.annotations.OpenApiProperty
 import io.github.tabilzad.ktor.getKDocComments
 import io.github.tabilzad.ktor.k1.visitors.KtorDescriptionBag
 import io.github.tabilzad.ktor.k1.visitors.toSwaggerType
@@ -44,7 +45,7 @@ internal class ClassDescriptorVisitorK2(
 ) : FirDefaultVisitor<ObjectType, ObjectType>() {
 
 
-    @OptIn(SealedClassInheritorsProviderInternals::class, SymbolInternals::class)
+    @OptIn(SealedClassInheritorsProviderInternals::class, SymbolInternals::class, PrivateForInline::class)
     override fun visitProperty(property: FirProperty, data: ObjectType): ObjectType {
         val coneTypeOrNull = property.returnTypeRef.coneTypeOrNull!!
         val type = if (coneTypeOrNull is ConeTypeParameterType && genericParameters.isNotEmpty()) {
@@ -74,6 +75,21 @@ internal class ClassDescriptorVisitorK2(
                 data
             }
 
+            property.findAnnotation(OpenApiProperty::class.simpleName) != null -> {
+                val formatAnnotation = property.findAnnotation(OpenApiProperty::class.simpleName)
+                val resolved = formatAnnotation?.let { FirExpressionEvaluator.evaluateAnnotationArguments(it, session) }
+                val dataType = resolved?.entries?.find { it.key.asString() == "type" }?.value?.result
+                val format = resolved?.entries?.find { it.key.asString() == "format" }?.value?.result
+                data.addProperty(
+                    property,
+                    objectType = ObjectType(
+                        type = dataType?.accept(StringResolutionVisitor(), ""),
+                        format = format?.accept(StringResolutionVisitor(), "")
+                    ), session
+                )
+                data
+            }
+
             else -> {
                 val fqClassName = type.fqNameStr()
 
@@ -105,6 +121,12 @@ internal class ClassDescriptorVisitorK2(
                                         )
                                     }
 
+                                    valueClassType.isMap -> {
+                                        acc.type = "object"
+                                        acc.additionalProperties = valueClassType.resolveItems()
+                                    }
+
+
                                     valueClassType.isAny -> {
                                         acc.type = "object"
                                     }
@@ -298,6 +320,11 @@ internal class ClassDescriptorVisitorK2(
             ObjectType("string").apply {
                 enum = typeSymbol?.resolveEnumEntries()
             }
+        } else if (type.isMap() && this.typeArguments.firstOrNull()?.type?.isString == true) {
+            ObjectType(
+                "object",
+                additionalProperties = this.typeArguments.lastOrNull()?.type?.resolveItems()
+            )
         } else {
             if (!classNames.names.contains(jetTypeFqName)) {
 
diff --git a/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/output/OpenApiSpec.kt b/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/output/OpenApiSpec.kt
index 3479463..22c2345 100644
--- a/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/output/OpenApiSpec.kt
+++ b/create-plugin/src/main/kotlin/io/github/tabilzad/ktor/output/OpenApiSpec.kt
@@ -45,6 +45,7 @@ data class OpenApiSpec(
         var type: String?,
         var properties: MutableMap<String, ObjectType>? = null,
         var items: ObjectType? = null,
+        var format: String? = null,
         var enum: List<String>? = null,
         @JsonIgnore
         override var fqName: String? = null,
diff --git a/create-plugin/src/test/resources/expected/RequestBody-expected.json b/create-plugin/src/test/resources/expected/RequestBody-expected.json
index 3da2af6..f41ea76 100644
--- a/create-plugin/src/test/resources/expected/RequestBody-expected.json
+++ b/create-plugin/src/test/resources/expected/RequestBody-expected.json
@@ -75,6 +75,20 @@
           }
         }
       }
+    },
+    "/v2/postInstantRequest" : {
+      "post" : {
+        "requestBody" : {
+          "required" : true,
+          "content" : {
+            "application/json" : {
+              "schema" : {
+                "$ref" : "#/components/schemas/sources.requests.InstantRequest"
+              }
+            }
+          }
+        }
+      }
     }
   },
   "components" : {
@@ -128,6 +142,16 @@
               }
             }
           },
+          "complexMapValueMap" : {
+            "type" : "object",
+            "properties" : { },
+            "additionalProperties" : {
+              "type" : "object",
+              "additionalProperties" : {
+                "$ref" : "#/components/schemas/sources.requests.ComplexMapValue"
+              }
+            }
+          },
           "complexNestedList" : {
             "type" : "array",
             "items" : {
@@ -213,7 +237,21 @@
             }
           }
         },
-        "required" : [ "list", "nestedList", "nestedMutableList", "complexList", "complexNestedList", "complexListStringMap", "complexListMap", "complexNestedListMap", "stringMap", "intValueMap", "complexValueMap", "enumValueMap", "complexEnumValueMap" ]
+        "required" : [ "list", "nestedList", "nestedMutableList", "complexList", "complexNestedList", "complexListStringMap", "complexListMap", "complexNestedListMap", "stringMap", "intValueMap", "complexValueMap", "enumValueMap", "complexEnumValueMap", "complexMapValueMap" ]
+      },
+      "sources.requests.InstantRequest" : {
+        "type" : "object",
+        "properties" : {
+          "date" : {
+            "type" : "string",
+            "format" : "iso 8601"
+          },
+          "formattedInstant" : {
+            "type" : "string",
+            "format" : "date-time"
+          }
+        },
+        "required" : [ "date", "formattedInstant" ]
       },
       "sources.requests.NestedRequest" : {
         "type" : "object",
diff --git a/create-plugin/src/test/resources/sources/RequestBody.kt b/create-plugin/src/test/resources/sources/RequestBody.kt
index 57192cb..abeaf7d 100644
--- a/create-plugin/src/test/resources/sources/RequestBody.kt
+++ b/create-plugin/src/test/resources/sources/RequestBody.kt
@@ -5,6 +5,7 @@ import io.ktor.server.application.*
 import io.ktor.server.request.*
 import io.ktor.server.routing.*
 import sources.requests.ComplexRequest
+import sources.requests.InstantRequest
 import sources.requests.NestedRequest
 import sources.requests.SimpleRequest
 
@@ -33,6 +34,10 @@ fun Application.requestBodyTest() {
             post("/postBodyComplexRequest") {
                 call.receive<ComplexRequest>()
             }
+
+            post("/postInstantRequest") {
+                call.receive<InstantRequest>()
+            }
         }
     }
 }
diff --git a/create-plugin/src/test/resources/sources/requests/RequestDataClasses.kt b/create-plugin/src/test/resources/sources/requests/RequestDataClasses.kt
index f86b97a..673a33b 100644
--- a/create-plugin/src/test/resources/sources/requests/RequestDataClasses.kt
+++ b/create-plugin/src/test/resources/sources/requests/RequestDataClasses.kt
@@ -1,5 +1,8 @@
 package sources.requests
 
+import io.github.tabilzad.ktor.annotations.OpenApiProperty
+import java.time.Instant
+
 data class SimpleRequest(
     val string: String,
     val integer: Int,
@@ -32,6 +35,7 @@ data class ComplexRequest(
     val complexValueMap: Map<String, ComplexMapValue>,
     val enumValueMap: Map<String, MyEnum>,
     val complexEnumValueMap: Map<String, List<MyEnum>>,
+    val complexMapValueMap: Map<String, Map<String, ComplexMapValue>>
 )
 
 data class ComplexMapValue(
@@ -42,6 +46,8 @@ data class ComplexMapKey(
     val something: Int
 )
 
+data class InstantRequest(@OpenApiProperty(type = "string", format = "iso 8601") val date: Instant, @OpenApiProperty(type = "string", format = "date-time") val formattedInstant: Instant)
+
 enum class MyEnum {
     ONE,
     TWO,