Argo CD Application vs ApplicationSet: What’s the Difference?

By Joris Jamers

If you’ve just started exploring GitOps with Argo CD, you’ve probably come across two key concepts: Application and ApplicationSet. At first glance, they might seem similar—they both deploy apps using Git—but they serve very different purposes, especially as your infrastructure grows.

In this post, we’ll break down what each one is, how they differ, and when you should use one over the other.

What is an Argo CD Application?

An Application in Argo CD is the basic building block of GitOps. Think of it as a recipe that tells Argo CD what to deploy, where to deploy it, and how to keep it in sync with Git.

What does it define?

  • A Git repository with your app configuration.
  • A path inside that repo where your manifests live.
  • A destination cluster and namespace.
  • Optional sync settings to automate deployments.

Here’s a simple example:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app
spec:
  destination:
    namespace: default
    server: https://kubernetes.default.svc
  source:
    repoURL: https://github.com/example/repo
    path: apps/my-app
  project: default
  syncPolicy:
    automated: {}

This will deploy your app from the Git repo into a Kubernetes namespace and keep it updated if anything changes in Git.

What is an Argo CD ApplicationSet?

Now imagine you have 10 microservices. Or maybe you need to deploy the same app to multiple environments—like dev, staging, and prod—or even to multiple clusters.

Creating one Application per deployment gets repetitive and hard to maintain.

This is where ApplicationSet comes in. It’s a higher-level controller that automatically generates multiple Applications based on a set of rules.

How does it work?

You define a generator (like a list of clusters or Git branches), and a template that tells Argo CD how to create Applications from that input.

Here’s an example using a list generator to deploy the same app to two clusters:

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: my-appset
spec:
  generators:
    - list:
        elements:
          - cluster: dev
            url: https://dev-cluster.example.com
          - cluster: prod
            url: https://prod-cluster.example.com
  template:
    metadata:
      name: '{{cluster}}-my-app'
    spec:
      destination:
        server: '{{url}}'
        namespace: default
      source:
        repoURL: https://github.com/example/repo
        path: apps/my-app
      project: default

This will generate two Applications, one for each cluster, with names like dev-my-app and prod-my-app.

Key Differences

Here’s a side-by-side comparison to make things clearer:

Feature Application ApplicationSet
Scope One app, one environment Many apps or environments
Best For Simple deployments Scalable, multi-cluster/multi-env setups
DRY (Don’t Repeat Yourself) Manual, repetitive Templated and reusable
Dynamic Behavior Static once created Auto-generates apps based on changing input
Supported Generators N/A Git, List, Matrix, SCM, Cluster, etc.
Complexity Beginner-friendly Slightly more advanced, but powerful

When Should You Use Each?

Use Application when:

  • You’re deploying a small number of services.
  • You want full control over each app.
  • You’re just getting started with GitOps.

Use ApplicationSet when:

  • You’re deploying the same app to multiple clusters or environments.
  • You have many services and want to avoid copy-pasting YAML.
  • You want to automate deployments based on Git branches, directories, or clusters.

Final Thoughts

Start simple with Argo CD Applications to get the feel of GitOps. As your projects grow and you need to scale out, ApplicationSets will become your best friend.

They help you stay organized, DRY, and make managing large environments much easier.

Next Steps

  • Try creating your first Application with Argo CD.
  • Once you’re comfortable, experiment with an ApplicationSet using the list generator.
  • Read the official docs on ApplicationSet for more examples.
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