Angular Developer track
Angular interview questions and answers
Angular interviews test components, change detection, signals, RxJS and dependency injection. Then you write or fix real code. Practice the concepts and the coding with follow-ups.
Questions
Interview questions and answers.
Real questions from this track, from easier to harder, with what a good answer covers. In the mock interview, each one comes with follow-ups based on what you say.
What is a component in Angular?
A good answer covers that a component is a class with a template, and the template is what the user sees.
What is a service, and when would you create one?
A good answer covers that a service is a plain class holding logic or state that is not about one screen.
What is an NgModule, and why do new Angular apps barely use them?
A good answer covers that a module used to group components, directives and pipes and declare what they could use.
Explain two-way data binding.
A good answer covers that the value flows from the class into the control and back again when the user types.
How does routing work in Angular?
A good answer covers that routes map a URL path to a component.
What is an Observable, and how is it different from a Promise?
A good answer covers that an Observable can emit many values over time, a Promise settles once.
What does the Angular CLI do for you?
A good answer covers that it creates the project and generates components, services and the rest to a consistent shape.
What kinds of data binding does Angular have?
A good answer covers that interpolation and property binding send data from the class to the template.
What is a directive, and what kinds are there?
A good answer covers that a directive adds behaviour to an element without being a component itself.
What is a pipe? Give an example of one you have used.
A good answer covers that a pipe transforms a value for display, inside the template.
What is dependency injection in Angular?
A good answer covers that a class asks for what it needs instead of creating it.
What are lifecycle hooks? Name a few and say what they are for.
A good answer covers that they are methods Angular calls at known points in a component's life.
How does a parent component pass data to a child, and how does the child send something back?
A good answer covers that data goes down and events go up, so the parent stays the owner of the state.
What are the different ways to build a form in Angular, and how would you pick?
A good answer covers that template-driven forms keep the form in the template and suit simple cases.
What is a template, and what can you put in it?
A good answer covers that a template is the HTML for a component, with Angular syntax mixed in.
What is the difference between interpolation and property binding?
A good answer covers that property binding sets a real property on an element or component, keeping the type.
What is the difference between a component's constructor and ngOnInit, and what belongs in each?
A good answer covers that the constructor runs when the class is created, before Angular has set any inputs.
Why do you use routerLink for navigation inside an Angular app instead of a plain href?
A good answer covers that a plain href makes the browser load the whole page again, restarting the app.
What is a signal?
A good answer covers that a signal holds a value and you read it by calling it.
What is change detection, and what makes it run?
A good answer covers that it is Angular checking whether what the template shows still matches the data.
What is the difference between a pure and an impure pipe?
A good answer covers that a pure pipe only runs again when its inputs change by reference.
What is an HTTP interceptor? Name something you would use one for.
A good answer covers that it sits between the app and the network and can see or change every request and response.
How would you test a component?
A good answer covers that you render it with its dependencies replaced by fakes you control.
What is a standalone component?
A good answer covers that it declares its own template dependencies in an imports array instead of being declared in a module.
What does the OnPush change detection strategy do?
A good answer covers that the component is only checked when something it depends on actually changes.
What does the async pipe do, and why is it usually recommended?
A good answer covers that it subscribes for you and renders the latest value.
What is a route guard? Give an example of when you would use one.
A good answer covers that a guard runs before a navigation and can allow it, block it or redirect.
What is a resolver, and when would you use one instead of loading data in the component?
A good answer covers that a resolver fetches data before the route activates and hands it to the component.
What is lazy loading, and why does it matter?
A good answer covers that a lazily loaded route's code is only downloaded when someone goes there.
What is inject(), and how is it different from constructor injection?
A good answer covers that inject() asks for a dependency as a function call instead of a constructor parameter.
What does providedIn: 'root' mean, and what is the alternative?
A good answer covers that root means one instance shared by the whole app, created the first time it is asked for.
What makes a directive structural rather than attribute?
A good answer covers that a structural directive adds or removes elements from the DOM.
What is content projection?
A good answer covers that a component can accept markup from its parent and render it in a chosen place.
Why does a list loop in a template need a track expression?
A good answer covers that it tells Angular which item in the new list is the same item as before.
What does map do, and what does switchMap do?
A good answer covers that switchMap starts a new inner stream per value and cancels the previous one.
What is ngOnDestroy for, and what should you clean up when a component goes away?
A good answer covers that it runs just before Angular removes the component, which is the last chance to release resources.
For a route like /users/:id, how does the component get the id, and what happens when the user goes from one user to another?
A good answer covers that the id comes from ActivatedRoute, or directly as an input with component input binding.
What is server-side rendering, and what is hydration?
A good answer covers that hydration is the client attaching to that existing markup instead of throwing it away and rebuilding.
How does Angular protect against XSS, and where can you still get it wrong?
A good answer covers that Angular treats interpolated values as untrusted and escapes them by default.
Many apps keep shared state in a service. When does that stop being enough?
A good answer covers that the strain shows when many features write the same state and nobody can tell who changed what.
What it covers
Topics.
How it works
How the mock interview runs.
Concept questions that start simple and get harder.
Follow-ups on every answer, so you explain the why.
One coding challenge in a live editor.
Your report scores technical correctness, problem-solving & tradeoffs, communication clarity, with quotes from your answers as proof.
Questions.
What Angular topics come up most?
Expect change detection, signals and RxJS streams. Dependency injection comes up a lot. You may also get routing and forms.
How does an Orin mock interview work?
You talk with Orin by voice, like a video call. It asks questions, listens and asks follow-ups based on what you said. Coding happens in a live editor and design on a live whiteboard. After the interview you get a report with quotes from your answers, what cost you points and what to practice next.
Is it free?
Your first interview is free: a 15-minute round with a short coding exercise. No card needed.
Practice the real thing.
A angular developer mock interview by voice, with follow-ups and feedback you can use. First interview free.
Start free interview