Onsite Interview Engineering: Front-End

What are we looking out for

Our Front-end Engineers use their solid computer science background and day-to-day production skills to estimate, analyse problems and make things beautiful. They use JavaScript strengths and their knowledge of the web platform to can architect the whole app right from the build script to tests.

Our Front-end Engineers work closely with Back-end engineers, product and, design teams.

Quantcast Engineers are passionate about technology and remain abreast with all the latest developments in Front-end field.

The Quantcast DNA

Your interviews are technical interviews but don’t be surprised with non- technical, behavioral questions. Here are the qualities we are looking for in our future Engineers:

  • Individuals at Quantcast are owners and experts who make significant impact on the organisation.
  • One constantly maintains the standard and raises the performance bar and ensure peers do the same.
  • Irrespective of title, everyone has the right to voice their opinions and challenge decisions. Leaders are expected to respect these rights.
  • We are the face of Quantcast to our customers and always aim to deliver results on point.

How should I be preparing for it?

  • You are expected to have strong basics, know algorithms, data structures.
    • Hash tables, Linked Lists, Breadth-first search, depth-first search, Quicksort / merge sort, Binary search, 2D arrays, Dynamic arrays, Binary search trees, Dynamic programming and Big-O analysis.
  • Understanding of System design- you shouldn’t be surprised when asked to design the front- end architecture of an application.
  • Areas to think about:
    • HTTP (At protocol level and as a means to expose an API)
    • Databases (indexes, query planning)
    • CDNs
    • Caching
    • Load balancers
    • Client & Server responsibilities
    • Front-end performance optimization techniques and trade-offs
  • It’s a JavaScript era, we expect you to be an expert in JavaScript and know the ins-and-outs of Javascript as a language and browser as a development platform.
  • Curiosity of trending in JS technology is definitely a plus! (to know JavaScript framework’s strength and latest Javascript technologies like ES6).
  • Make sure you are comfortable with semantic HTML5 and CSS3, it’s the bread and butter of front- end development.
  • Web performance, build systems- in addition to general programming best practices, interviewers will look at performance implications.
    • Understanding of browser rendering path
    • Diagnosing optimization opportunities
    • Knowledge of key metrics to triangular potential performance bottlenecks
  • Algorithms / Data structure and inheritance in JavaScript.
  • Testing- at Quantcast we believe that testing an important part of software development. Expect testing questions with a focus on code testability, automation.
  • Expect to answer in-depth questions about Angular & React if you have prior experience with these frameworks.
  • Be able to estimate and analyze a problem correctly be vocal about your thought process.


Your interview is a conversation, we want you to leave our office knowing what the hiring manager wants, what the team is like, what your workday would be like and the tools, technologies you’d use to do your job.

Have a strategy for asking your interviewer questions, here is what we recommend:

  • Think of things you want to know about us before you will accept an offer, interview us for:
    • The position (responsibilities, challenges, career progression)
    • Team interactions (team structure, meetings, project management tools/ methodologies, interactions with other teams).
    • Development process (development time, code review, QA testing) Open source, Codebase/ architecture (test suite, codebase documentation, build process/ automation, product hosting)
    • Front- End stack  (or Back- End stack/ Systems Administration) (rationale behind the stack? New tools?), Product voice (product ideas, meaty stuff pushed to release)  
    • Culture, Company, competitors
  • Ask questions that are relevant to the person and the position you are interviewing for.

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