Web Developer interview questions

Question

I read an article today that listed some basic questions about web development:

1. Describe how POST data was submitted to a server by a browser.

2. Explain a number of HTTP status codes (except maybe 404 and 500).

3. Explain SOLID or name a design pattern.

4. Explain ways to improve a page load speed or user experience.

The author says "if you can’t answer the questions above there are a lot of people who wouldn’t think of you as a Senior Web Developer."

My questions are:

1. How relevant are these questions in respect to real life web programming and scalability?

2. How true is that statement? In other words, do you consider this knowledge a requirement to be considered a Senior Web Developer?

3. I was able to answer all the questions, too easily it seemed, so I'm wondering whether it is effective to use these or similar questions to screen developers rather than asking them to write sample code.

Answer 1

Those aren't the worst interview questions I've ever heard, but it is possible to be a great Senior Web Developer who gets things done and not know the answer to all of those.

I wouldn't count someone out just for not being able to explain the lower-level details of how a POST works, and I wouldn't think any less of a person who couldn't name some HTTP status code, so why even bother asking these types of questions? These types of things could be explained to the person in the first hour of their first day on the job if necessary, or discovered via Google as needed. That's how I learned them when I needed to.

You can find out much more about a person's abilities by asking them to work out a real problem, either on the whiteboard or in pseudo-code. Then ask them to talk you through some of their past projects, successes, failures, etc. Much more useful than "name this thing, name that thing" questions, which mostly amount to trivia.

Answer 2

As the author of the article I can probably add some thought: none of those questions are difficult questions. A web developer who doesn't understand POST vs GET or http status codes is lacking the very foundations of web development. Many of the guys I've interviewed wanting exorbitant salaries can't answer these questions.

I.e they may have "been around" for a while but definitely aren't people I'd hire for senior roles. Apologies if you thought I considered these things as being hard. For context though, a senior dev can take these questions and expand them greatly.

Can you write/explain a POST request as an http request including header? What is your recall like if you had to write this request on a notepad? (ie you've not only seen an http 1.1 header and know what it looks but you've seen it enough that you can semi-remember it) How is a HEAD request different from POST/Get? In .Net land how is a PostBack different from a standard HTTP Post? What are your thoughts about this abstraction (love/hate?) and why? Etc etc.

They are what I call "feeder" questions. I have many of them, and they always start as beginner questions that evolve into discussion pieces. The best part about asking simple things, is you get real insight into the passion, loves/hates, fanatacism/religious thoughts on some topics and much more (ie. if someone starts talking about Nuget and mentions how it is like Ruby gems, this shows me that aren't just .Net devs and have a broader web programming view).

As a disclaimer though, these questions work for me but may not for you.

I also often do written problem solving/live coding tests, but I run mine a little differently from the norm. I like to give them a problem, ask them to talk through how they plan to solve it, and then get them to write (attempt to write?) pseudo-code (on paper with a pen) to solve it. This puts even the best programmers out of their element, and I feel gives me more insight into how they deal with a weird problem under strange conditions. I then ask how they would make their code testable, or how to refactor it. It is more of a discussion piece than anything, as this gives me insight into how they problem solve, what they know of any framework features that could help them, and much much more.

Smart guys are smart whether they know the latest IDE features or not. These are the people I want. I also will always have a brief I need to match though, so if I'm hiring for a web developer and your can't remember some HTTP status codes... well you aren't really a web developer (in my opinion). Again this is based on what I need so it might be different for you.

Answer 3

Given the general rule of thumb that I prefer to follow, if a question can be answered within ~10 seconds using Google, its a worthless question. Questions 1&2 fall into this category. Question 3 is borderline, it has potential to reveal understanding if taken further, but really only asks for buzzwords that really aren't that necessary to know in order to be a good developer, especially design pattern names. Question 4 is a good question because its asks about higher level thinking not just regurgitation of memorized facts.

Personally I would say questions along the lines of the first three are entirely useless for interviewing a senior developer. You are paying senior developers to think, not be a dictionary, the questions asked should reflect that.

Answer 4

How relevant are these questions in respect to real life web programming and scalability?

Most of them seem more or less relevant to me. Remembering HTTP status codes by heart isn't so much, but understanding the reason behind them, their allocation scheme etc. pretty much is.

Design patterns are almost ubiquitous nowadays, and IMHO basic familiarity with these and with SOLID principles is expected from an experienced developer (although not everyone is of the same opinion).

How true is that statement?

100%. If you can’t answer these questions (or any number of other, more or less arbitrarily selected ones) there will certainly be a lot of people who wouldn’t think of you as a Senior Web Developer :-)

How relevant this is to your real problem solving skills is a different issue though. "Senior developer" is a weakly defined term, it can mean a lot of different things to different people at different companies.

I was able to answer all question and it was pretty just too easy so am thinking : Using similar questions as interview questions for screening developers rather then write sample code question be effective or not

Questions like this may be useful for filtering applicants, but definitely not as the only method during the interview.

Answer 5

Questions #1 & 2 tell me that the user has a basic knowledge of what's going on behind the scenes of whatever language/framework they are using to do web programming. I stand by the belief that the stateless nature of HTTP makes web development somewhat more tricky (not necessarily more difficult) than thick client programming.

Knowing that the client is submitting a request to the server and expecting a reply (and understanding what that reply means) is necessary to debug low-level problems that inevitably crop up in any web application.

Question 3 to me proves that developer has more than a "copy-paste" mentality, is interested in the app development field and is passionate enough to learn best-practices or a philosophy around app development

Question 4 again shows that a developer has not just created an application but has worked to refactor or improve it - and has a better understanding of the underlying components.

All being said, these are some good questions -- I would ask even a mid-level developer coming in to answer.

Answer 6

The questions are very relevant - in my opinion, Seniors are expected to

Demonstrate experience in analyzing problems

• Improving page load performance issues is a common task on any web project and allows the interviewer to get a good idea of the 'depth' of knowledge - improvements can be gained from browser, server and database alike, so should be a fair assessment of the whole tier / stack.

Demonstrate a hunger for knowledge and the humility to seek advice from the wider profession

• It is hard to imagine that a Developer working for 5 years or so hasn't run into GoF, the 3 Amigos, Fowler, Evans or Uncle Bob etc somewhere along the line. Not doing your fair share of 'keeping up' is intellectually lazy IMO.

Know how things 'really' work underneath the skin

• After a few hours worth using Fiddler, Wireshark or Chrome's network analyser, most devs will be able to give a pretty good explanation of how HTTP really works between browser and server. So no problems with the HTTP and 404 errors.

Code writing tests are great for screening junior devs. However, seniors also need to have good communication skills. The interviewer shouldn't need to put the candidate in front of a computer to tell whether or not he / she can write code.

Answer 7

It's far more important for a senior developer to know about software architecture than it is for them to know about "nuts and bolts" stuff like the example questions given. The senior developer role has a tendency in a lot of cases to basically be a systems analyst role. The kind of questions you've listed are okay for establishing if a lower level "code monkey" knows the basic tools of their trade, but its entirely possible that a person poorly suited to a senior developer role could answer them all correctly, or that someone who would be great for the role would fail to answer.

You should be more concerned with testing their knowledge of systems architecture. A senior developer will probably be drawing up an overview of the system that the dev team is going to implement, so it's vital that (s)he gets the architectural details right. The rest of the team will basically be implementing his/her design, after all and their work will only ever be as good as his/hers.

You might want to provide your prospective developer with a spec for a simple system (say a blog with multiple users, commenters, etc) and see what kind of design they come up with, how well it's documented, and so on.