For years, I believed I knew what made someone a senior engineer. The more technologies they knew, the harder problems they could solve, and the more sophisticated code they wrote, the more senior they seemed.
Today, I would hire a different person. Not the one who writes the best code. The one I would trust when everything stops going according to plan. Those are two very different things.
Seniority Is Hard To Measure
The industry has taught us to measure seniority using things that are easy to count: years of experience, frameworks, certifications and technologies listed on a CV.
All of those matter. Every senior engineer should have strong technical foundations and understand the consequences of technical decisions. But that's only the beginning.
The qualities that truly define seniority are much harder to measure: responsibility, ownership, communication, judgement and calm under pressure. They rarely appear on a CV, yet they often determine whether a project succeeds or fails.
Technical Excellence And Seniority Are Not The Same Thing
Throughout my career, I've worked with incredibly talented engineers. People who solved problems faster than anyone else, understood complex systems in remarkable depth and consistently impressed me with their technical abilities.
Their expertise was never the problem. In fact, it was one of the biggest assets a team could have.
What I eventually learned, however, was that technical excellence alone doesn't automatically make someone a senior engineer.
As responsibilities grow, success depends on much more than writing great code. It becomes about explaining ideas, aligning technology with business, helping others make better decisions and staying calm when things stop going according to plan.
The more responsibility a role carries, the less it becomes about writing code.
The People Everyone Turns To
Every team has people everyone naturally goes to when something important happens. They aren't always the strongest programmers and they don't always know every answer.
What makes them different is their perspective. They understand technology, business and people, and they know how to connect all three. They consistently make good decisions, especially when there isn't an obvious one.
Looking back, that's when I realized I had been measuring the wrong things.
Senior Engineers Deliver Results
Today, one phrase defines seniority for me better than any job title: deliver results.
Sometimes delivering results means writing code. Sometimes it means simplifying a solution. Sometimes it means saying "no". Sometimes it means helping a less experienced colleague. Sometimes it means having a difficult conversation with a stakeholder. And sometimes it simply means finding a window when every door seems closed.
Code is only one of the tools. Delivering results is the real objective.
Responsibility Beyond Your Own Code
Early in my career, I looked for people with the deepest technical knowledge. Today, I look for people I can trust.
Real projects rarely fail because someone didn't know one more framework. They fail where technology, business and people intersect. That's exactly where senior engineers make the biggest difference.
They don't take responsibility only for the code they write. They take responsibility for the outcome.
Seniority begins where responsibility for your own code ends.
Final Thoughts
The longer I work in software, the less interested I am in how many technologies someone knows. I'm far more interested in what happens when a project stops going according to plan.
That's when you discover who your senior engineers really are. Not by the code they write, but by whether everyone around them can rely on them.
Responsibility defines seniority. Experience only prepares you for it.