AKS vs App Service vs Container Apps - Quick Guide

Azure gives you three ways to run a container, and interviewers use this question to see if you default to Kubernetes out of habit or actually think through the tradeoffs. It comes up constantly in Azure DevOps and platform engineering interviews because picking the wrong service is an expensive, hard-to-reverse mistake.

The answer interviewers want

There are three tiers, and you should think of them as a decision tree rather than three equal options.

App Service is for simple web apps. If you've got a straightforward app or API that doesn't need complex orchestration, this is the starting point. It's the least operational overhead.

Container Apps is for microservices without Kubernetes complexity. When you need to scale out multiple services, handle event-driven workloads, or run several containers that talk to each other, but you don't want to manage a cluster, this is the next step up.

AKS is for when you need full Kubernetes control. That means custom schedulers, specific networking setups, operators, CRDs, or other Kubernetes-native features that only a real cluster gives you.

The real decision tree interviewers want to hear: start with App Service. Move to Container Apps when you need more scaling flexibility than App Service gives you. Only reach for AKS when you actually need Kubernetes features, not just because it's what everyone else is running.

Why interviewers ask this

This question tests whether you understand that operational complexity has a cost, and whether you can justify a service choice based on actual requirements instead of resume-driven development. A candidate who jumps straight to "AKS for everything" is signaling that they haven't had to run a cluster at 3AM, or haven't thought about what that ongoing maintenance burden actually buys the business.

Follow-ups to expect

What would make you move from Container Apps to AKS later? Needing a specific Kubernetes feature that Container Apps doesn't expose, like a custom scheduler, a particular networking model, or operators and CRDs the app depends on.

What would make you move from App Service to Container Apps? Needing to scale multiple services independently or handle more complex, event-driven workloads than a single web app model supports.

Is this decision reversible? It's generally easier to move up the tiers, from App Service to Container Apps to AKS, than to over-provision AKS early and then try to simplify back down once a team has built processes around a cluster.

The common wrong answer

Most candidates answer this by describing what each service does in isolation, App Service hosts web apps, AKS runs Kubernetes, Container Apps runs containers, without ever stating a decision order. That tells the interviewer you know the products but haven't actually had to choose between them under a real constraint. The stronger answer is the decision tree: start simple, move up only when a specific, concrete requirement forces it, and never choose AKS by default.