Questions to ask your interviewer: development and emergencies

Carl Vitullo
May 17, 2018 · 7 min read

In my career I have worked for 6 different companies, ranging from 4th hire at a startup to a senior developer at a Fortune 100 financial company. This leaves me an uncommon perspective on how a wide range of companies operate. Changing jobs so many times has given me a lot of experience interviewing, as well.

I’ve compiled a list of questions that I ask, wish I had asked, or plan to ask in the future. Each question has details about why I find that question valuable and what answers I expect. It ended up being a lot longer than I expected, so I’m splitting it up into several parts so it isn’t too overwhelming:

The development environment is a product of the developers building it and the culture created by managers, and a good development environment means fewer emergencies. I read something years ago that stuck with me: “Instead of saying “I don’t have time” try saying “it’s not a priority,” and see how that feels.” (As best I can tell, it’s from a 2012 Wall Street Journal piece by Laura Vanderkam). Given competing priorities, too many companies forego maintenance tasks. “There isn’t time this sprint,” is something I’ve heard all too often. “We’ll pick it up later.”

Instead of saying “I don’t have time” try saying “it’s not a priority,” and see how that feels.

These moments of deferred maintenance stack up, turning into a culture that doesn’t value details. Organizations that value maintenance have happier, more effective developers. Hopefully, the questions here will help you spot on one from the outside.

Development environment

How long does it take to do a complete deployment?

Long deployments are often manual, and more prone to errors and accidental downtime. Long deployments increase cycle times, which makes people more nervous to make changes. This question can also serve as a proxy for how non-developers view improvements that aren’t user-facing. User experience should be a priority, but a good developer experience helps deliver value more often (and it’s good for morale and recruitment. Happy developers tell their friends).

Photo by Markus Spiske on Unsplash

I work in frontend, and as such generally ship static files as build artifacts. I prefer to hear that deployments are less than 15 minutes, and that it doesn’t need to be run a specific person. I’m ecstatic if they have the ability to build several testing environments at once, but I’ve found that rare.

What is a big pull request, in lines of code or files affected? How long is it open?

Small PRs are simpler to manage. They cause fewer merge conflicts, and the ones that do occur are smaller. Smaller PRs mean you’re merging more frequently, which means they’re following modern continuous delivery strategies. Large, long-lived branches can be a sign of a lack of rigor in managing tasks or inexperienced senior developers, who should be leading the charge on maintenance tasks. Large PRs are the only option in codebases where many modules are tightly coupled, so shipping small PRs is a signal that the code is more likely to be well structured.

To me, a big PR might be 2000 lines of code, or touching 20 different files. I prefer to open PRs early as work-in-progress and might have it open for half of a two-week sprint. I do this to ask for input and code review from coworkers early on, even if we can’t pair together on the task. When developers open PRs only when the task is done, it should touch no more than a handful of files and change less than a few hundred lines of code–at most.

Another positive signal I look for is when the team ships changes behind feature flags. Feature flags are easier to use when code has clear separation of responsibilities. Seeing feature flags gives me more confidence that the code is well maintained, but it’s not a silver bullet. I’ve worked on spaghetti code that use feature flagging as well.

How many repositories would I touch to make routine changes?

Photo by John Carlisle on Unsplash

Some projects might be in a monorepo so large that there are a thousand commits a day. Other projects might be a web of interlinked dependencies scattered across a dozen repositories. This question should kick off a conversation about project structure and code sharing.

For young companies that only have a single product, having a large number of repositories is a red flag. Making changes across many repositories takes longer and requires more care, and young companies should be focused on creating something people want. For established companies, I’d want to ask how they manage code duplication and internal libraries. It’s not a simple problem and there are many approaches.

How often do developers have to make simultaneous changes across repositories?

Needing to coordinate changes across repositories signals tighter coupling between modules. It’s a red flag to have different services that need to be deployed at the same time–it demonstrates that the services are fragile. Robust and durable services must be able to compensate for predictable failures. If it’s difficult to deploy a new version of a service, it’s a hint that the service doesn’t have well defined responsibilities.

Deploying a module shouldn’t require a simultaneous deployment of something else. A new patch version of an internal dependency shouldn’t break the code that consumes it. Changes to an HTTP API should be backwards-compatible with existing clients. Security patches to libraries may need a series of deployments before they’re completely rolled out, but that isn’t due to fragility. The best answer for this is “never,” though it might happen due to unintentional coupling.

Emergency situations

These are questions that I added in direct response to previous experiences. They are not questions I asked, but are questions that, if I had asked, I might have saved myself several stressful months.

How often do you have major outages? What constitutes a major outage for you?

Photo by Matt Howard on Unsplash

Major outages should be infrequent, by which I mean with several months with no events. The clarification is important to avoid a miscommunication due to different definitions of a “major outage.” You may think of major outages as any time the customer can’t access any feature, but they may view it as when the app stops responding altogether. Their answer might be truthful but use such a different yardstick that it doesn’t answer your question.

Frequent major outages could indicate code that is tremendously difficult to change. It could be significant numbers of unknown dependencies in the codebase. Maybe they’ve had large amounts of turnover and lost undocumented knowledge. They may have avoided paying interest on tech debt for years. A software company that can’t consistently run its own code is in dire straits.

Do you have a defined process for handling an outage?

For a startup that’s still young, a lack of process might well be a good sign — the code has worked reliably so far. A lack of process means that they haven’t had enough outages to merit codifying a process around them. The more established a company is, the more concerned I am if they haven’t thought through how to handle an outage. Large companies should have processes in place for how to handle major issues and prevent them from reoccurring.

Would I be expected to be on-call?

Photo by Niklas Hamann on Unsplash

It’s up to you whether this is to be expected or an unreasonable request. The more 9s of uptime expected from your code, the more likely you are to have some amount of on-call duty. When your code runs is also a factor. If you’ll be responsible for ingesting data from third parties overnight, you’re more likely to have to deal with unexpected breakage at odd hours than web or mobile developers. You’ll need to talk to your peers and identify whether on-call is a reasonable expectation for the work you prefer doing.

What does your on-call process look like?

If you’ve established that you will be on-call, know what you’re getting into! How often does the on-call person get paged, how it will impact paid time off, what the escalation process is. Being on-call is a much larger responsibility that just writing code, so know what you’re getting into.

I’ve been required to be on-call for two jobs that I’ve worked. In both cases, I was on call for a week at a time, with a second developer as a backup. It ended up being a big factor in why I left both positions. If I were interviewing for a role that expected me to be on-call, I’d want to dig deeply into the why they instituted the policy and what they’re doing to reduce the frequency of pages.


Thanks for reading the second group of questions to ask your interviewer! Stay tuned for part three, with questions about opportunities for personal growth, in a few days. I’m on Twitter as @cvitullo, and I moderate Reactiflux, a chatroom for React developers (shoutout to the jobs-advice channel), and Nodeiflux, a chatroom for Node.JS developers. If you have any questions or suggestions, reach out!

Carl Vitullo

Written by

Just some guy. On Twitter https://twitter.com/cvitullo Also the internet https://blog.vcarl.com/

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade