From managing expectations throughout the company to writing the invitation mail, preparing an interview takes a considerable amount of time—rightfully so, because it’s the most important meeting you’ll be having this week.

This is Part #1 of my series on Awesome Technical Interviews. Part #2 can be found here.


I guess a fair bit of warning is appropriate at this point: my experience comes from working with young companies, with teams that like to be involved in processes like hiring. My clients usually don’t do rocket science, but develop apps and software for businesses and private people. This also means that most of the time, having very specific skills is nice, but by no means a necessity.

Seeking clarification

Let’s start with the goal I have in mind for everything laid out in this blog post series:

Minimize surprises for the interviewee and everyone else involved at every point in the hiring process.

Everyone means everyone. Everyone in the team should know the criteria applied to the interviews. I must be aware of the team’s expectations towards the new hire. The interviewee should know everything about what is going to happen on the day of the interview. The team should know who’s going to visit the office and why.

The complexity of the project and the role I’m hiring for is something that is very important to me. I make sure it is well communicated to the teams and line managers. Chances are, a company does nothing that hasn’t been done before on a technical level, so they might not need a specialist, but a curious person that is willing to get familiar with a new ecosystem.

Does the company have the capacity to train people and do they have a proper mentorship process? If so, that means technical requirements become less important - what else is it one should focus on then?

I strive to make sure that everyone is aware and in agreement about the criteria important to the company and of the criteria that they explicitly deemed not important. Interviewing handbooks like the one Medium published this year are a valuable resource to find out what a company’s criteria should be.

Take-home exercise or pair programming?

I leave it to the interviewee to choose between a take-home exercise or a pair programming interview. There are some downsides to take-home exercises, just as there are for on-site pair programming interviews, but remember that the person interviewing for the job might have other obligations that make it hard for them to visit the office for a few hours—just imagine if you applied to a bunch of companies and they all asked you to come by for an afternoon that early into the hiring process!

Should the interviewee choose a take-home exercise, I will not let this decision factor into the decision at all. After they sent around their solution, I invite them to the office and let them walk me through the code for half an hour as an exercise.

In the following though, I’m assuming that the interviewee picked the pair programming interview.

Picking a task

Having facilitated countless coding katas at our meetup in Berlin, I hereby promise that a task cannot be small enough for an hour of pair programming. Kata-Log, a list of coding exercises compiled by the amazing @egga_de is a great source of inspiration for me.

My personal take on the task is this though: I love to use production code as an exercise. What I did in the past is to pick something I have done recently in a code base and delete most tests and the implementation. If the code base is too big, it might make sense to delete distracting aspects of it for the exercise.

Using production code has some great advantages:
I am deeply familiar with the Ins and Outs of the code in front of me. Furthermore, I have solved the problem before and can explain the requirements in depth. The interviewee can catch a short glimpse at the code they’d be working with and ultimately, they will get to know the domain we are working with a little.

Fair warning though: If you’re frustrated with the current state of your code base and if things can unexpectedly break, it might not be the perfect fit for an interview.

No matter if you choose a coding kata or your production code base, there is one thing to keep in mind: The task should be as easy as possible, solvable by someone familiar with the code base in less than 30 minutes.

Let me give you two examples:

You can already filter the displayed results by limiting the price. Our task will be similar: Adding a filter to limit the results by their rating. Please implement the proper business logic and UI parts.

Implement a function that will return a human readable presentation of a given time span in seconds, e.g. prettyPrint(140) => "2 minutes, 20 seconds".
After that, add an option to only show the biggest unit and the second-biggest unit, given that it is not zero, e.g. prettyPrint(90012, brevity: true) => "1 day, 1 hour.

The invitation

Now that I’ve picked the task, it’s time to draft the invitation for the interviewee.

I, of course, remember how nervous I’ve been at every interview, checking the location of the office and the scheduled time every other minute as the interview came closer, which is why I now pay close attention to being very verbose when it comes to how the interview is going to happen.

Remember my goal: Minimize surprises for the interviewee and everyone else involved at every point in the hiring process.


nice to meet you! I’m the freelancer currently developing the front-end at $COMPANY (find me on Twitter! 😄) and I’m very much looking forward to pairing with you next Tuesday.

If you want, feel free to bring your own laptop with the dev setup you are comfortable with. I will have my laptop (Atom, Chrome & GNOME3 on a Dell XPS) with me as well.

The codebase is a create-react-app app with react-router v4 and redux. Right now, I’m working on filtering the search results and presenting them to the user. I imagine we could pair on getting a specific filter to work (e.g. filtering by price).

We will have water and coffee provided by the facilities at the office. Our office is on the 4th floor right next to the bathrooms in the lobby. I will send you a calendar invitation with the exact address.

We will pair for at most one hour, the whole interview will take at most two hours.

Should you have any trouble finding the office, feel free to give me a call via +491XXXXXXXXX.
Until then, if you have any other questions, feel free to send me a mail :)

Looking forward to meeting you!

With the invitation sent, let me walk you through how the day of the interview is going to go down in Part #2.

If you want me to bring this process to your company, send me a mail at so we can talk about the specifics over a coffee or via video chat.