Mar 21, 2026 · 7 min read · Hiring Tips

12 Red Flags in Tech Interviews That Predict Bad Hires

A bad hire costs EUR 50-150K when you count recruiting, onboarding, lost productivity, and the disruption of re-hiring. Most of these could have been caught in the interview. Here are the signals to watch for.

1. Cannot explain their own code simply

Critical

If they built it but cannot explain it to a non-expert, they either did not build it or do not truly understand it. Both are bad.

2. Blames every failure on the team

Critical

"The project failed because the PM was incompetent." Everyone has been on bad teams. The question is: what did YOU do about it?

3. Only talks about technologies, never about problems solved

High

"I used Kubernetes and Terraform." Great. But what business problem did it solve? Senior engineers think in outcomes, not tools.

4. Refuses to say "I don't know"

High

Making up answers instead of admitting gaps. The best engineers are comfortable with uncertainty. The worst fake confidence.

5. No questions about the team or culture

Medium

A candidate who only asks about tech stack and salary is optimizing for resume, not fit. They will leave for the next shiny thing.

6. Wants to rewrite everything from scratch

High

"I would throw away the current codebase and start fresh." This shows contempt for existing work and unrealistic ambition. Refactor, don't rewrite.

7. Has never disagreed with a manager

Medium

Either they are not senior enough to have opinions, or they suppress them. Both are problems for a role that requires independent judgment.

8. Cannot describe a failure they caused

High

Everyone who has shipped code has broken something. If they cannot share a story, they are hiding it or have never had real responsibility.

9. Over-engineers the system design

Medium

Microservices for 100 users. Event sourcing for a CRUD app. Complexity is not intelligence — simplicity is.

10. Dismissive of testing

High

"Tests slow me down." In a team, untested code is a liability. This attitude scales badly and causes incidents.

11. Job-hops every 6-12 months with no pattern

Medium

One short stint is fine. Three in a row suggests they either cannot commit or cannot perform. Ask about each one.

12. Negotiates aggressively before showing interest

Low

Leading with compensation before understanding the role suggests they are shopping, not evaluating. The best candidates want to know what they would be building.

The counter-argument

No single red flag should disqualify a candidate. Look for patterns. One flag is a conversation starter. Three flags is a pattern. And always give candidates the benefit of interview nerves — follow up on concerns before making a final decision.