Years of experience tell you very little in an interview. The strongest signal I look for is simple: the candidate talks about a decision they got wrong without being asked, and explains what it taught them about the next one.
Green flag one: owning a wrong decision
Anyone can describe a project that went well. Senior engineers have made enough real decisions to have made bad ones, and they have thought about why. When someone brings that up unprompted, and can connect the mistake to how they decide now, it tells me they learn from consequences rather than from résumé lines.
Green flag two: on-call before tech stack
The second one: they ask about on-call before they ask about the tech stack.
That question tells me they have carried the pager. They know the stack is the easy part to learn, and that how a team handles production, incidents and sleep is what actually shapes the job.
Takeaways
- Experience shows up as reflection on mistakes, not years on a CV.
- Volunteering a wrong decision and its lesson is a strong senior signal.
- Asking about on-call before tech stack shows someone who has owned production.
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