As I mentioned earlier in my comment, if possible, you can insert a message and specify initialVisibilityDelay with 30 min delay when your http function get the request, and then you can use a queue trigger function to process the queue message and do some tasks.
If you create Azure functions on Azure portal, you can reference Microsoft.WindowsAzure.Storage
and use the following code to add message in your http trigger function.
Reference assemblies and import namespaces
#r "Microsoft.WindowsAzure.Storage"
using System.Net;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Queue;
Add message and specify initialVisibilityDelay
CloudStorageAccount storageAccount = CloudStorageAccount.Parse("{storage_connection_string}");
CloudQueueClient queueClient = storageAccount.CreateCloudQueueClient();
CloudQueue queue = queueClient.GetQueueReference("mymes");
queue.CreateIfNotExists();
CloudQueueMessage message = new CloudQueueMessage("{message_body}");
queue.AddMessage(message, initialVisibilityDelay: TimeSpan.FromMinutes(30));
Besides, you can create a function triggered by Azure Queue storage to process your queue messages.