🕒 Handling Time Zones in .NET 6: Quartz.NET vs Hangfire for Scheduled Jobs

🧾 Scenario: Daily Invoice Email at 9 AM Local Time

Requirements:

• Users are in India, UK, and US

• Email should be sent at 9 AM local time

• Server runs in UTC

• App is built in .NET 6 Web API

🔧 Quartz.NET vs Hangfire (Quick Comparison)

Feature	Hangfire	Quartz.NET
Time Zone Support	❌ Manual	✅ Native
Ideal For	Delayed jobs	Scheduled jobs
Dashboard	✅ Yes	❌ No
Retry/Error Handling	✅ Yes	⚠️ Manual
Distributed Setup	✅ Yes	✅ Yes

🛠️ Option 1: Quartz.NET for Time-Sensitive Jobs

✅ Best for scheduled tasks at specific times in specific time zones

📦 Job Class

public class InvoiceJob : IJob
{
    public Task Execute(IJobExecutionContext context)
    {
        Console.WriteLine($"Invoice job running at {DateTime.UtcNow}");
        // Custom logic: fetch users in IST and send emails
        return Task.CompletedTask;
    }
}

🗓️ Register Job in Program.cs (or a Hosted Service)

IScheduler scheduler = await StdSchedulerFactory.GetDefaultScheduler();
await scheduler.Start();

IJobDetail job = JobBuilder.Create<InvoiceJob>()
    .WithIdentity("invoiceJob", "billing")
    .Build();

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("dailyTrigger", "billing")
    .WithCronSchedule("0 0 9 ? * *", x => x
        .InTimeZone(TimeZoneInfo.FindSystemTimeZoneById("India Standard Time")))
    .Build();

await scheduler.ScheduleJob(job, trigger);

✅ This job runs daily at 9 AM IST, no matter where your server is hosted.

🛠️ Option 2: Hangfire for Delayed or Event-Based Jobs

✅ Best for fire-and-forget or delayed jobs

📦 Delayed Job Example

BackgroundJob.Schedule(() => SendEmail(userId), TimeSpan.FromMinutes(10));

📦 Recurring Job Example

RecurringJob.AddOrUpdate(
    "daily-invoice",
    () => SendDailyInvoices(),
    Cron.Daily
);

⚠️ Time Zone Limitation: Hangfire schedules in server time.

To support multiple time zones:

• Store user time zones in the database

• Convert local time to UTC when scheduling

• Handle logic in the job execution if needed

🏗️ Run Jobs on a Separate Server

Both Quartz.NET and Hangfire can run in a dedicated .NET 6 Worker Service:

+-------------------+      +-------------------------+
| Web API           | -->  | .NET 6 Worker (Jobs)    |
+-------------------+      +-------------------------+
         Database             Job Scheduling Engine

✅ This setup improves scalability, separation of concerns, and distributed job processing.

🎯 Which Should You Use?

Use Case	Best Choice
Time-specific jobs in user time zones	✅ Quartz.NET
Delayed jobs or event-driven triggers	✅ Hangfire
Need dashboard, retries, failure tracking	✅ Hangfire
Hybrid needs (scheduled + triggered)	✅ Use both

---

✅ Best Practices

• Store all timestamps in UTC

• Convert to local time in the UI

• Avoid relying on server's local time

• Use Quartz.NET for precision, Hangfire for flexibility