How to Vet Senior Developers in Under an Hour (Without Leetcode Hazing)

Note: This story was written with AI assistance and edited by me. It also appeared in an earlier version elsewhere, and I own the rights to both.

Senior developers do not need to reverse a linked list on a whiteboard. You already know they can code. What you need to learn is how they think, decide and work with others.

You can do that in under an hour. Here is the format I like.

Why puzzle interviews fail at senior level

Algorithm puzzles test practice, not experience. A great senior engineer who has not studied puzzles in years can fail them. A recent bootcamp graduate who grinds problem sets can pass them. The result is a filter that does not match the job.

Strong candidates also find these interviews insulting, and they have options. If your process feels like hazing, you lose them.

The 60-minute structure

Minutes 0 to 10: Context.

Describe the role and a real problem your team faces. Let them ask questions. Good seniors ask a lot, and the quality of their questions tells you plenty.

Minutes 10 to 30: Walk through a past project.

Ask them to take you through one system they built. Then dig in:

• What was the hardest decision, and what did you reject?

• What would you change today?

• What broke in production and how did you handle it?

You are listening for ownership, honest tradeoffs and clear explanations.

A few follow-ups I keep ready: "Who disagreed with you, and how did that get resolved?" and "What did you learn about the system after launch that you did not know before?" Strong seniors answer with names, numbers and specifics. Weak answers stay vague, or every success is "we" and every failure is "they".

Minutes 30 to 50: A realistic design problem.

Give a small, real scenario from your business. Ask how they would approach it. There is no single right answer. Watch how they scope the problem, ask about constraints and communicate risk.

For example, you might say: "Our customers upload large files and the processing step is timing out. How would you approach it?" A good senior will ask how large, how often and what the failure costs before suggesting anything. They will name two or three options, pick one and say what could go wrong with it. A weaker candidate jumps straight to a favorite tool.

Minutes 50 to 60: Their questions.

Ask what they want to know about you. Senior people interview you back, and how they do it shows what they value.

Make it consistent

Use the same structure and the same rubric for every candidate. Score each area from 1 to 4 right after the call: communication, technical judgment, ownership, collaboration. Write down evidence for each score. Do not rely on a gut feeling alone.

Here is how I keep the scores honest. A 1 means a clear concern. A 2 means mixed signals. A 3 means solid and what you would expect from a senior. A 4 means they taught you something. Write one sentence of evidence next to every number, such as "Explained why they rejected microservices and what it cost them." Score before you talk to anyone else on the panel, then compare notes. That keeps one loud opinion from deciding the outcome. Also resist rewarding charm. A smooth talker with no specifics should not outscore a quiet engineer with concrete answers.

Where AI helps

AI can keep the format consistent, capture the conversation and produce a clean summary for the hiring team. It does not replace the interviewer's judgment. It just makes sure the interview is structured and nothing gets lost.

What the hour will not tell you

It will not prove someone can deliver every day for two years. So follow it with a short paid trial task or a reference call with someone who worked with them directly.

Keep the trial task small, a few hours at most, and pay for it. On the reference call, ask what the person was like when a project went badly. That answer tells you more than any interview question.

The payoff

A one-hour process like this is faster, fairer and better at predicting performance. Hiring well was the engine of every team I have helped grow. Strong seniors raise the whole team. Run this once with one candidate and score it. You will see within an hour whether the format fits your team.