diff --git a/packages/dynamite/dynamite/lib/src/builder/client.dart b/packages/dynamite/dynamite/lib/src/builder/client.dart
index 16cac51c..51a4fefa 100644
--- a/packages/dynamite/dynamite/lib/src/builder/client.dart
+++ b/packages/dynamite/dynamite/lib/src/builder/client.dart
@@ -354,29 +354,7 @@ Iterable<Method> buildTags(
               nullable: dartParameterNullable,
             ).dartType;
 
-            if (result.name == 'String') {
-              if (parameter.schema?.pattern != null) {
-                code.write('''
-if (!RegExp(r'${parameter.schema!.pattern!}').hasMatch(${toDartName(parameter.name)})) {
-  throw Exception('Invalid value "\$${toDartName(parameter.name)}" for parameter "${toDartName(parameter.name)}" with pattern "\${r'${parameter.schema!.pattern!}'}"'); // coverage:ignore-line
-}
-''');
-              }
-              if (parameter.schema?.minLength != null) {
-                code.write('''
-if (${toDartName(parameter.name)}.length < ${parameter.schema!.minLength!}) {
-  throw Exception('Parameter "${toDartName(parameter.name)}" has to be at least ${parameter.schema!.minLength!} characters long'); // coverage:ignore-line
-}
-''');
-              }
-              if (parameter.schema?.maxLength != null) {
-                code.write('''
-if (${toDartName(parameter.name)}.length > ${parameter.schema!.maxLength!}) {
-  throw Exception('Parameter "${toDartName(parameter.name)}" has to be at most ${parameter.schema!.maxLength!} characters long'); // coverage:ignore-line
-}
-''');
-              }
-            }
+            buildPatternCheck(result, parameter).forEach(code.writeln);
 
             final defaultValueCode = parameter.schema?.$default != null
                 ? valueToEscapedValue(result, parameter.schema!.$default.toString())
@@ -610,6 +588,27 @@ final _response = await $client.doRequest(
   }
 }
 
+Iterable<String> buildPatternCheck(
+  final TypeResult result,
+  final openapi.Parameter parameter,
+) sync* {
+  final value = toDartName(parameter.name);
+  final name = "'$value'";
+
+  final schema = parameter.schema;
+  if (result.name == 'String' && schema != null) {
+    if (schema.pattern != null) {
+      yield "checkPattern($value, RegExp(r'${schema.pattern!}'), $name); // coverage:ignore-line";
+    }
+    if (schema.minLength != null) {
+      yield 'checkMinLength($value, ${schema.minLength}, $name); // coverage:ignore-line';
+    }
+    if (schema.maxLength != null) {
+      yield 'checkMaxLength($value, ${schema.maxLength}, $name); // coverage:ignore-line';
+    }
+  }
+}
+
 Iterable<String> buildAuthCheck(
   final Map<openapi.Response, List<int>> responses,
   final MapEntry<String, openapi.PathItem> pathEntry,
diff --git a/packages/dynamite/dynamite/lib/src/builder/imports.dart b/packages/dynamite/dynamite/lib/src/builder/imports.dart
index 7e15b857..97c25371 100644
--- a/packages/dynamite/dynamite/lib/src/builder/imports.dart
+++ b/packages/dynamite/dynamite/lib/src/builder/imports.dart
@@ -17,6 +17,7 @@ List<Spec> generateImports(final AssetId outputId) => [
       Directive.import('package:collection/collection.dart'),
       Directive.import('package:dynamite_runtime/content_string.dart'),
       Directive.import('package:dynamite_runtime/http_client.dart'),
+      Directive.import('package:dynamite_runtime/utils.dart'),
       Directive.import('package:universal_io/io.dart'),
       const Code(''),
       Directive.export('package:dynamite_runtime/http_client.dart'),
diff --git a/packages/dynamite/dynamite_runtime/lib/src/string_checker.dart b/packages/dynamite/dynamite_runtime/lib/src/string_checker.dart
new file mode 100644
index 00000000..accfb49f
--- /dev/null
+++ b/packages/dynamite/dynamite_runtime/lib/src/string_checker.dart
@@ -0,0 +1,26 @@
+/// Checks the [input] against [pattern].
+///
+/// Throws an `Exception` containing the [parameterName] if the `pattern` does not match.
+void checkPattern(final String input, final RegExp pattern, final String parameterName) {
+  if (!pattern.hasMatch(input)) {
+    throw Exception('Invalid value "$input" for parameter "$parameterName" with pattern "${pattern.pattern}"');
+  }
+}
+
+/// Checks the [input] length against [minLength].
+///
+/// Throws an `Exception` containing the [parameterName] if the `input` is to short.
+void checkMinLength(final String input, final int minLength, final String parameterName) {
+  if (input.length < minLength) {
+    throw Exception('Parameter "$input" has to be at least $minLength characters long');
+  }
+}
+
+/// Checks the [input] length against [maxLength].
+///
+/// Throws an `Exception` containing the [parameterName] if the `input` is to long.
+void checkMaxLength(final String input, final int maxLength, final String parameterName) {
+  if (input.length > maxLength) {
+    throw Exception('Parameter "$input" has to be at most $maxLength characters long');
+  }
+}
diff --git a/packages/dynamite/dynamite_runtime/lib/utils.dart b/packages/dynamite/dynamite_runtime/lib/utils.dart
index 30f229d5..c8d7b711 100644
--- a/packages/dynamite/dynamite_runtime/lib/utils.dart
+++ b/packages/dynamite/dynamite_runtime/lib/utils.dart
@@ -1 +1,2 @@
+export 'src/string_checker.dart';
 export 'src/uri.dart';
diff --git a/packages/nextcloud/lib/src/api/files.openapi.dart b/packages/nextcloud/lib/src/api/files.openapi.dart
index d97ff316..af8b02b4 100644
--- a/packages/nextcloud/lib/src/api/files.openapi.dart
+++ b/packages/nextcloud/lib/src/api/files.openapi.dart
@@ -11,6 +11,7 @@ import 'package:built_value/standard_json_plugin.dart';
 import 'package:collection/collection.dart';
 import 'package:dynamite_runtime/content_string.dart';
 import 'package:dynamite_runtime/http_client.dart';
+import 'package:dynamite_runtime/utils.dart';
 import 'package:universal_io/io.dart';
 
 export 'package:dynamite_runtime/http_client.dart';
@@ -120,9 +121,7 @@ class FilesApiClient {
 // coverage:ignore-end
     path = path.replaceAll('{x}', Uri.encodeQueryComponent(x.toString()));
     path = path.replaceAll('{y}', Uri.encodeQueryComponent(y.toString()));
-    if (!RegExp(r'^.+$').hasMatch(file)) {
-      throw Exception('Invalid value "$file" for parameter "file" with pattern "${r'^.+$'}"'); // coverage:ignore-line
-    }
+    checkPattern(file, RegExp(r'^.+$'), 'file'); // coverage:ignore-line
     path = path.replaceAll('{file}', Uri.encodeQueryComponent(file));
     final response = await _rootClient.doRequest(
       'get',
diff --git a/packages/nextcloud/lib/src/api/files_reminders.openapi.dart b/packages/nextcloud/lib/src/api/files_reminders.openapi.dart
index e0d6bb7e..ac6169fc 100644
--- a/packages/nextcloud/lib/src/api/files_reminders.openapi.dart
+++ b/packages/nextcloud/lib/src/api/files_reminders.openapi.dart
@@ -10,6 +10,7 @@ import 'package:built_value/standard_json_plugin.dart';
 import 'package:collection/collection.dart';
 import 'package:dynamite_runtime/content_string.dart';
 import 'package:dynamite_runtime/http_client.dart';
+import 'package:dynamite_runtime/utils.dart';
 import 'package:universal_io/io.dart';
 
 export 'package:dynamite_runtime/http_client.dart';
@@ -109,11 +110,7 @@ class FilesRemindersApiClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^1$').hasMatch(version)) {
-      throw Exception(
-        'Invalid value "$version" for parameter "version" with pattern "${r'^1$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(version, RegExp(r'^1$'), 'version'); // coverage:ignore-line
     path = path.replaceAll('{version}', Uri.encodeQueryComponent(version));
     path = path.replaceAll('{fileId}', Uri.encodeQueryComponent(fileId.toString()));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
@@ -164,11 +161,7 @@ class FilesRemindersApiClient {
 
 // coverage:ignore-end
     queryParameters['dueDate'] = dueDate;
-    if (!RegExp(r'^1$').hasMatch(version)) {
-      throw Exception(
-        'Invalid value "$version" for parameter "version" with pattern "${r'^1$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(version, RegExp(r'^1$'), 'version'); // coverage:ignore-line
     path = path.replaceAll('{version}', Uri.encodeQueryComponent(version));
     path = path.replaceAll('{fileId}', Uri.encodeQueryComponent(fileId.toString()));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
@@ -221,11 +214,7 @@ class FilesRemindersApiClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^1$').hasMatch(version)) {
-      throw Exception(
-        'Invalid value "$version" for parameter "version" with pattern "${r'^1$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(version, RegExp(r'^1$'), 'version'); // coverage:ignore-line
     path = path.replaceAll('{version}', Uri.encodeQueryComponent(version));
     path = path.replaceAll('{fileId}', Uri.encodeQueryComponent(fileId.toString()));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
diff --git a/packages/nextcloud/lib/src/api/provisioning_api.openapi.dart b/packages/nextcloud/lib/src/api/provisioning_api.openapi.dart
index 95fc8e16..ca925063 100644
--- a/packages/nextcloud/lib/src/api/provisioning_api.openapi.dart
+++ b/packages/nextcloud/lib/src/api/provisioning_api.openapi.dart
@@ -11,6 +11,7 @@ import 'package:built_value/standard_json_plugin.dart';
 import 'package:collection/collection.dart';
 import 'package:dynamite_runtime/content_string.dart';
 import 'package:dynamite_runtime/http_client.dart';
+import 'package:dynamite_runtime/utils.dart';
 import 'package:universal_io/io.dart';
 
 export 'package:dynamite_runtime/http_client.dart';
@@ -733,11 +734,7 @@ class ProvisioningApiGroupsClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^.+$').hasMatch(groupId)) {
-      throw Exception(
-        'Invalid value "$groupId" for parameter "groupId" with pattern "${r'^.+$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(groupId, RegExp(r'^.+$'), 'groupId'); // coverage:ignore-line
     path = path.replaceAll('{groupId}', Uri.encodeQueryComponent(groupId));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
     final response = await _rootClient.doRequest(
@@ -787,11 +784,7 @@ class ProvisioningApiGroupsClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^.+$').hasMatch(groupId)) {
-      throw Exception(
-        'Invalid value "$groupId" for parameter "groupId" with pattern "${r'^.+$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(groupId, RegExp(r'^.+$'), 'groupId'); // coverage:ignore-line
     path = path.replaceAll('{groupId}', Uri.encodeQueryComponent(groupId));
     if (search != '') {
       queryParameters['search'] = search;
@@ -849,11 +842,7 @@ class ProvisioningApiGroupsClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^.+$').hasMatch(groupId)) {
-      throw Exception(
-        'Invalid value "$groupId" for parameter "groupId" with pattern "${r'^.+$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(groupId, RegExp(r'^.+$'), 'groupId'); // coverage:ignore-line
     path = path.replaceAll('{groupId}', Uri.encodeQueryComponent(groupId));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
     final response = await _rootClient.doRequest(
@@ -901,11 +890,7 @@ class ProvisioningApiGroupsClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^.+$').hasMatch(groupId)) {
-      throw Exception(
-        'Invalid value "$groupId" for parameter "groupId" with pattern "${r'^.+$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(groupId, RegExp(r'^.+$'), 'groupId'); // coverage:ignore-line
     path = path.replaceAll('{groupId}', Uri.encodeQueryComponent(groupId));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
     final response = await _rootClient.doRequest(
@@ -958,11 +943,7 @@ class ProvisioningApiGroupsClient {
 // coverage:ignore-end
     queryParameters['key'] = key;
     queryParameters['value'] = value;
-    if (!RegExp(r'^.+$').hasMatch(groupId)) {
-      throw Exception(
-        'Invalid value "$groupId" for parameter "groupId" with pattern "${r'^.+$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(groupId, RegExp(r'^.+$'), 'groupId'); // coverage:ignore-line
     path = path.replaceAll('{groupId}', Uri.encodeQueryComponent(groupId));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
     final response = await _rootClient.doRequest(
@@ -1011,11 +992,7 @@ class ProvisioningApiGroupsClient {
     }
 
 // coverage:ignore-end
-    if (!RegExp(r'^.+$').hasMatch(groupId)) {
-      throw Exception(
-        'Invalid value "$groupId" for parameter "groupId" with pattern "${r'^.+$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(groupId, RegExp(r'^.+$'), 'groupId'); // coverage:ignore-line
     path = path.replaceAll('{groupId}', Uri.encodeQueryComponent(groupId));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
     final response = await _rootClient.doRequest(
@@ -1801,11 +1778,11 @@ class ProvisioningApiUsersClient {
     queryParameters['key'] = key;
     queryParameters['value'] = value;
     path = path.replaceAll('{userId}', Uri.encodeQueryComponent(userId));
-    if (!RegExp(r'^(?!enable$|disable$)[a-zA-Z0-9_]*$').hasMatch(collectionName)) {
-      throw Exception(
-        'Invalid value "$collectionName" for parameter "collectionName" with pattern "${r'^(?!enable$|disable$)[a-zA-Z0-9_]*$'}"',
-      ); // coverage:ignore-line
-    }
+    checkPattern(
+      collectionName,
+      RegExp(r'^(?!enable$|disable$)[a-zA-Z0-9_]*$'),
+      'collectionName',
+    ); // coverage:ignore-line
     path = path.replaceAll('{collectionName}', Uri.encodeQueryComponent(collectionName));
     headers['OCS-APIRequest'] = oCSAPIRequest.toString();
     final response = await _rootClient.doRequest(
diff --git a/packages/nextcloud/lib/src/api/theming.openapi.dart b/packages/nextcloud/lib/src/api/theming.openapi.dart
index 66d75dcf..4ed2e605 100644
--- a/packages/nextcloud/lib/src/api/theming.openapi.dart
+++ b/packages/nextcloud/lib/src/api/theming.openapi.dart
@@ -11,6 +11,7 @@ import 'package:built_value/standard_json_plugin.dart';
 import 'package:collection/collection.dart';
 import 'package:dynamite_runtime/content_string.dart';
 import 'package:dynamite_runtime/http_client.dart';
+import 'package:dynamite_runtime/utils.dart';
 import 'package:universal_io/io.dart';
 
 export 'package:dynamite_runtime/http_client.dart';
@@ -186,9 +187,7 @@ class ThemingIconClient {
 
 // coverage:ignore-end
     path = path.replaceAll('{app}', Uri.encodeQueryComponent(app));
-    if (!RegExp(r'^.+$').hasMatch(image)) {
-      throw Exception('Invalid value "$image" for parameter "image" with pattern "${r'^.+$'}"'); // coverage:ignore-line
-    }
+    checkPattern(image, RegExp(r'^.+$'), 'image'); // coverage:ignore-line
     path = path.replaceAll('{image}', Uri.encodeQueryComponent(image));
     final response = await _rootClient.doRequest(
       'get',