Jobs (Queues) vs. Events
When to use each one?
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When a heavy task needs to run — which potentially could idle the program, or multiple actions need to occur when some action happens, you would need to run the task outside the main request-response flow.
That's where jobs and events come in. Though they might seem similar, they serve different purposes.
Job
A job is a task that runs in the background, often on a schedule or triggered by a system process outside the main request-response cycle (e.g., sending an email).
Jobs are a powerful tool for handling resource-intensive, time-consuming, or non-urgent processes.
Useful when
- Run scheduled tasks (like cron jobs)
- Perform logic that doesn’t need to run immediately
- Process large files (PDFs, images, etc.)
- Sync data with third-party services or APIs
E.g.: A system that automatically generates and emails financial reports every night at midnight. No user action is required; it just happens as scheduled.
Event
An event is a signal that something has happened in your application. Events can be generated by users (e.g., clicking a button) or by the system (e.g., a database update). It doesn't do anything by itself — instead, one or more listeners react to that event.
Events are a great way to decouple your logic. Rather than hardcoding all the logic inside one method, you can fire an event and let other parts of your system decide how to respond.
Useful when
- Broadcast in real-time when a specific action occurs (like
UserRegistered) - Trigger multiple follow-up actions
- Improve code modularity and separation of concerns
E.g.: In a chat application, when someone sends you a message, an event triggers a notification on your phone.
| Scenario | Job | Event |
|---|---|---|
| Perform a heavy or background task | 🟢 | 🔴 |
| Execute a one-off task with no need for notification | 🟢 | 🔴 |
| Retry failed operations | 🟢 | 🔴 |
| Trigger multiple reactions from one action | 🔴 | 🟢 |
| Let the system know something happened | 🔴 | 🟢 |
| Decouple business logic | 🔴 | 🟢 |
Simple Analogy
- A job is like an alarm clock that rings at the same time every day, whether you're awake or not
- An event is like a doorbell that rings when someone presses it, regardless of the time and is listened by everybody inside
Combining Events and Jobs
It is possible to combine both simultaneously, that is, send an event when the user performs an action, and potentially, one of the listeners runs a job in the background, like sending a welcome email.
Final Thoughts
Knowing when to use jobs and events is essential if your goal is performance, scalability, and maintainability.
Use jobs for automated, scheduled tasks and events for real-time interactions.