diff --git a/src/Keycloak.Net/KeycloakClient.cs b/src/Keycloak.Net/KeycloakClient.cs
index ac26b598..fc9a7e99 100644
--- a/src/Keycloak.Net/KeycloakClient.cs
+++ b/src/Keycloak.Net/KeycloakClient.cs
@@ -16,15 +16,6 @@ public partial class KeycloakClient
             NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore
         });
 
-        static KeycloakClient()
-        {
-            JsonConvert.DefaultSettings = () => new JsonSerializerSettings
-            {
-                ContractResolver = new CamelCasePropertyNamesContractResolver(),
-                NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore
-            };
-        }
-
         private readonly Url _url;
         private readonly string _userName;
         private readonly string _password;
@@ -47,7 +38,7 @@ public KeycloakClient(string url, Func<string> getToken)
         {
             _getToken = getToken;
         }
-        
+
         private IFlurlRequest GetBaseUrl(string authenticationRealm) => new Url(_url)
             .AppendPathSegment("/auth")
             .ConfigureRequest(settings => settings.JsonSerializer = s_serializer)
diff --git a/src/Keycloak.Net/RolesById/KeycloakClient.cs b/src/Keycloak.Net/RolesById/KeycloakClient.cs
index 88a8510c..a773d7f3 100644
--- a/src/Keycloak.Net/RolesById/KeycloakClient.cs
+++ b/src/Keycloak.Net/RolesById/KeycloakClient.cs
@@ -5,7 +5,6 @@
 using Flurl.Http.Content;
 using Keycloak.Net.Models.Common;
 using Keycloak.Net.Models.Roles;
-using Newtonsoft.Json;
 
 namespace Keycloak.Net
 {
@@ -52,7 +51,7 @@ public async Task<bool> RemoveRolesFromCompositeAsync(string realm, string roleI
         {
             var response = await GetBaseUrl(realm)
                 .AppendPathSegment($"/admin/realms/{realm}/roles-by-id/{roleId}/composites")
-                .SendJsonAsync(HttpMethod.Delete, new CapturedJsonContent(JsonConvert.SerializeObject(roles)))
+                .SendJsonAsync(HttpMethod.Delete, new CapturedJsonContent(s_serializer.Serialize(roles)))
                 .ConfigureAwait(false);
             return response.IsSuccessStatusCode;
         }