diff --git a/bin/configs/ktorm-schema.yaml b/bin/configs/ktorm-schema.yaml
index aff895cb279..d3c5beb9a33 100644
--- a/bin/configs/ktorm-schema.yaml
+++ b/bin/configs/ktorm-schema.yaml
@@ -1,7 +1,7 @@
 generatorName: ktorm-schema
 outputDir: samples/schema/petstore/ktorm
-inputSpec: modules/openapi-generator/src/test/resources/2_0/petstore.yaml
+inputSpec: modules/openapi-generator/src/test/resources/3_0/petstore.yaml
 templateDir: modules/openapi-generator/src/main/resources/ktorm-schema
 additionalProperties:
   hideGenerationTimestamp: true
-  importModelPackageName: org.openapitools.client.models
\ No newline at end of file
+  importModelPackageName: org.openapitools.client.models
diff --git a/bin/configs/nim.yaml b/bin/configs/nim.yaml
index 136a92764c3..13a27a6b764 100644
--- a/bin/configs/nim.yaml
+++ b/bin/configs/nim.yaml
@@ -1,6 +1,6 @@
 generatorName: nim
 outputDir: samples/client/petstore/nim
-inputSpec: modules/openapi-generator/src/test/resources/2_0/petstore.yaml
+inputSpec: modules/openapi-generator/src/test/resources/3_0/petstore.yaml
 templateDir: modules/openapi-generator/src/main/resources/nim-client
 additionalProperties:
   packageName: petstore
diff --git a/samples/client/petstore/nim/petstore/apis/api_pet.nim b/samples/client/petstore/nim/petstore/apis/api_pet.nim
index 3644e392340..b2f77c2bdbb 100644
--- a/samples/client/petstore/nim/petstore/apis/api_pet.nim
+++ b/samples/client/petstore/nim/petstore/apis/api_pet.nim
@@ -39,10 +39,12 @@ template constructResult[T](response: Response): untyped =
     (none(T.typedesc), response)
 
 
-proc addPet*(httpClient: HttpClient, body: Pet): Response =
+proc addPet*(httpClient: HttpClient, pet: Pet): (Option[Pet], Response) =
   ## Add a new pet to the store
   httpClient.headers["Content-Type"] = "application/json"
-  httpClient.post(basepath & "/pet", $(%body))
+
+  let response = httpClient.post(basepath & "/pet", $(%pet))
+  constructResult[Pet](response)
 
 
 proc deletePet*(httpClient: HttpClient, petId: int64, apiKey: string): Response =
@@ -78,10 +80,12 @@ proc getPetById*(httpClient: HttpClient, petId: int64): (Option[Pet], Response)
   constructResult[Pet](response)
 
 
-proc updatePet*(httpClient: HttpClient, body: Pet): Response =
+proc updatePet*(httpClient: HttpClient, pet: Pet): (Option[Pet], Response) =
   ## Update an existing pet
   httpClient.headers["Content-Type"] = "application/json"
-  httpClient.put(basepath & "/pet", $(%body))
+
+  let response = httpClient.put(basepath & "/pet", $(%pet))
+  constructResult[Pet](response)
 
 
 proc updatePetWithForm*(httpClient: HttpClient, petId: int64, name: string, status: string): Response =
diff --git a/samples/client/petstore/nim/petstore/apis/api_store.nim b/samples/client/petstore/nim/petstore/apis/api_store.nim
index 3c518e8dd31..a2f018b7cf3 100644
--- a/samples/client/petstore/nim/petstore/apis/api_store.nim
+++ b/samples/client/petstore/nim/petstore/apis/api_store.nim
@@ -57,10 +57,10 @@ proc getOrderById*(httpClient: HttpClient, orderId: int64): (Option[Order], Resp
   constructResult[Order](response)
 
 
-proc placeOrder*(httpClient: HttpClient, body: Order): (Option[Order], Response) =
+proc placeOrder*(httpClient: HttpClient, order: Order): (Option[Order], Response) =
   ## Place an order for a pet
   httpClient.headers["Content-Type"] = "application/json"
 
-  let response = httpClient.post(basepath & "/store/order", $(%body))
+  let response = httpClient.post(basepath & "/store/order", $(%order))
   constructResult[Order](response)
 
diff --git a/samples/client/petstore/nim/petstore/apis/api_user.nim b/samples/client/petstore/nim/petstore/apis/api_user.nim
index 87bef06818e..618477db595 100644
--- a/samples/client/petstore/nim/petstore/apis/api_user.nim
+++ b/samples/client/petstore/nim/petstore/apis/api_user.nim
@@ -38,22 +38,22 @@ template constructResult[T](response: Response): untyped =
     (none(T.typedesc), response)
 
 
-proc createUser*(httpClient: HttpClient, body: User): Response =
+proc createUser*(httpClient: HttpClient, user: User): Response =
   ## Create user
   httpClient.headers["Content-Type"] = "application/json"
-  httpClient.post(basepath & "/user", $(%body))
+  httpClient.post(basepath & "/user", $(%user))
 
 
-proc createUsersWithArrayInput*(httpClient: HttpClient, body: seq[User]): Response =
+proc createUsersWithArrayInput*(httpClient: HttpClient, user: seq[User]): Response =
   ## Creates list of users with given input array
   httpClient.headers["Content-Type"] = "application/json"
-  httpClient.post(basepath & "/user/createWithArray", $(%body))
+  httpClient.post(basepath & "/user/createWithArray", $(%user))
 
 
-proc createUsersWithListInput*(httpClient: HttpClient, body: seq[User]): Response =
+proc createUsersWithListInput*(httpClient: HttpClient, user: seq[User]): Response =
   ## Creates list of users with given input array
   httpClient.headers["Content-Type"] = "application/json"
-  httpClient.post(basepath & "/user/createWithList", $(%body))
+  httpClient.post(basepath & "/user/createWithList", $(%user))
 
 
 proc deleteUser*(httpClient: HttpClient, username: string): Response =
@@ -84,8 +84,8 @@ proc logoutUser*(httpClient: HttpClient): Response =
   httpClient.get(basepath & "/user/logout")
 
 
-proc updateUser*(httpClient: HttpClient, username: string, body: User): Response =
+proc updateUser*(httpClient: HttpClient, username: string, user: User): Response =
   ## Updated user
   httpClient.headers["Content-Type"] = "application/json"
-  httpClient.put(basepath & fmt"/user/{username}", $(%body))
+  httpClient.put(basepath & fmt"/user/{username}", $(%user))