Conducting Interviews for Coding Projects

If you’ve ever sat on either side of a coding interview, you know how awkward it can get. The interviewer is trying to figure out if this person can actually do the job, and the candidate is trying not to freeze up while someone watches them type. Done badly, the whole thing feels like a waste of everyone’s time. Done well, it can tell a company almost everything it needs to know.

This guide walks through how to run interviews for coding projects in a way that’s fair, useful, and doesn’t leave candidates hating the experience.

Why Technical Interviews Actually Matter

A resume can say “5 years of React experience” and still not tell you whether someone can think through a problem on the spot. That’s where technical interview questions come in. They’re not really about catching someone out — they’re about seeing how a person works when things get tricky.

Someone might know a programming language inside and out but completely fall apart when asked to explain their thinking, or they might write messy code but solve the actual problem faster than anyone else. Both of these things matter, just in different ways depending on the role.

Building a Coding Interview Process That Works

A lot of companies run interviews on the fly. Someone grabs a question from an old email, asks it, and moves on. This works sometimes, but it usually leads to inconsistent results — and candidates can tell when an interview feels thrown together.

A solid coding interview process doesn’t need to be complicated. It just needs a bit of structure:

• Know what the job actually needs before writing a single question. A role focused on fixing bugs in old code needs different questions than one focused on building something new from scratch
• Keep the format consistent across candidates applying for the same role, so everyone gets a fair shot and it’s easier to compare notes afterward
• Mix it up — a short coding problem, a bit of system thinking, and a conversation about real work they’ve done
• Don’t rush people. Watching someone panic under a tight clock doesn’t tell you how they’d actually perform on the job

What Kinds of Questions Should You Ask?

There’s no single set of questions that works for every role. A software developer hiring and someone working mostly on UI will face different challenges, and that’s fine — the questions should reflect that.

Problem-Solving Questions

This is the classic “write some code” part of the interview. Maybe it’s finding duplicates in a list, or reversing a string, or something slightly trickier. The actual problem matters less than how the person works through it.

Do they ask questions before diving in? Do they think out loud? Do they test their own code once it’s written? These little things often say more than whether the final answer is perfect.

System Design Questions

For people applying to more senior roles, it helps to ask how they’d approach building something bigger — say, a basic booking system or a simple chat app.

There’s genuinely no “right” answer here. What you’re looking for is whether they think about the stuff that matters later: what happens when more people start using it, where data gets stored, how different pieces talk to each other.

Questions About Past Work

Sometimes the most useful question is simply: “Tell me about a project you worked on that didn’t go smoothly. What happened?”

How someone talks about a past struggle — whether they own their part in it, what they learned, how they handled the pressure — often says more about how they’ll fit into a team than any coding puzzle could.

A Few Programming Assessment Tips Worth Following

Running the test is one thing. Reviewing it fairly is a whole different skill, and it’s one that often gets less attention than it deserves. A few programming assessment tips that tend to help:

• Pay attention to how someone got to the answer, not just whether the answer is correct. A working solution with a slightly clumsy approach can still show solid thinking
• Ask them to walk you through their code afterward. People who understand what they wrote can usually explain it in plain words, even if it’s not polished
• Skip the gotcha questions. Asking about some obscure edge case in a language’s syntax doesn’t tell you much except whether someone happened to read that particular blog post
• Let people use the tools they’d normally use — search engines, docs, whatever. Nobody codes from memory all day, every day, and pretending otherwise doesn’t help anyone
• Tell candidates something useful afterward, even if it’s just a quick note on what went well. It costs almost nothing and people remember it

Mistakes That Show Up More Than You’d Think

One is testing for the wrong thing entirely. If the actual job is mostly maintaining an existing codebase, but the interview is all about writing algorithms from a blank page, the test isn’t really measuring what matters for that role.

Another is cramming too much into one day. Back-to-back interview rounds with no breaks can wear down even strong candidates, and by round four, nobody’s giving their best.

Looking at the Whole Person, Not Just the Code

The strongest signals sometimes come from things that aren’t directly about coding at all. How does someone react when told their solution has a bug? Do they get defensive, or do they dig in and try to fix it?

Do they ask questions about the team, the project, how decisions get made? That kind of curiosity often points to someone who’ll stick around and actually care about the work, not just clock in and out.

Don’t Forget the Candidate’s Side of Things

While the company is sizing up the candidate, the candidate is also sizing up the company — and a messy interview process can quietly cost you good people, even when the job offer itself is fine.

Starting on time, giving clear instructions before any coding test, and actually following up afterward (even with a no) all go a long way. None of this is hard, but it’s surprising how often it gets skipped.

Running Interviews Remotely

These days, a lot of coding interviews process happen over video calls, especially for remote roles. It sounds simple, but tech issues can derail an otherwise good interview fast — a laggy screen share or a code editor that won’t load eats into time and rattles candidates.

A quick test run beforehand helps avoid most of this. It’s also worth being thoughtful about time zones — scheduling someone for an interview at an awful hour their time isn’t a great first impression, even if it’s convenient for the interviewer.

Final Thoughts

Good coding interviews don’t need fancy tricks or impossible questions. They need a bit of planning, a fair mix of question types, and a process that treats candidates like people rather than test subjects. Get that right, and the rest — finding people who can actually do the job and fit the team — tends to follow.

FAQs

1. How long should a coding interview last?

Somewhere around 45 minutes to an hour per round usually works well. Push much beyond that and people start running out of steam, especially later in a multi-round process.

2. Is it okay to let candidates search online during a coding test?

Honestly, yes. That’s how most software developers hiring actually work day to day, so blocking it just makes the test less realistic — not harder in a useful way.

3. How should junior and senior developer interviews differ?

Junior developers recruitment usually get more straightforward coding problems to check the basics. Senior developer recruitment tends to face more open-ended questions about design decisions, trade-offs, and how they’ve handled tricky situations before.

4. How many rounds of interviews are reasonable?

Two or three tend to hit the sweet spot — enough to cover technical interview questions , problem-solving, and a general sense of fit, without dragging the process out so long that good candidates lose interest.

5. What’s the best way to keep remote interviews fair?

Test the tools beforehand, give everyone the same instructions and time limits, and try to be reasonable about scheduling across time zones. Small things, but they add up.