Principal Engineer vs Senior Engineer
Principal Engineer vs Senior Engineer
Back in my day …
In the old days there was a short period when a senior engineer would excel beyond the scope of their role and the company would offer a promotion to be a classical manager of a team. Then the people management and other non technical work became the focus of the role and the title and the technical expertise would evaporate and the job would become people manager and domain expert.
Think of the role of principal engineer as freezing that period of time when the company recognizes that you as a senior engineer are exceeding the scope of your job, but instead of promoting you to a different type of job in management, you get a promotion to that expanded role you’re already doing. It’s a win-win for both the company and engineers who are looking for career growth but don’t want to be managers.
Principals
A Principal Engineer maintains deep technical expertise while operating at a broader strategic level than a Senior Engineer. Both roles require excellent coding skills and system design knowledge, but Principal Engineers must also guide multi-year technical direction and drive cross-organization impact. While Senior Engineers focus primarily on complex problems within their team, Principal Engineers leverage their technical depth to identify systemic issues affecting multiple teams and architect scalable solutions.
The trend in tech today is that management roles are increasingly expected to retail a high level of technical knowledge it’s going to be interesting to see how this evolves in the coming years, especially with AI agent augmentation.
Leveling up
To advance from Senior to Principal, engineers must expand their influence beyond individual contributions, lead architectural decisions, and build consensus across teams … all while maintaining hands-on technical excellence.
Success comes from combining strong coding fundamentals with strategic thinking, mentoring other engineers, and making technology choices that make sense to business goals.
Principal Soft Skills
- Multitasking
- Communication
- Organization and Leadership
- Thinking broadly
- Glue work
Multitasking - juggle multiple high-priority initiatives simultaneously, like reviewing critical architecture decisions or mentoring team members while staying involved in key technical discussions and maintaining awareness of ongoing projects.
Communication - explain complex technical concepts clearly to both engineers and non-technical stakeholders, write detailed documentation, and do presentations and workshops on important technical topics.
Organization and Leadership - the leadership type for a principal is typically leading by influence, which can have varying levels of difficulty depending on your company culture and and reporting incentives.Success requires systematically tracking numerous projects and dependencies, and guiding teams toward solutions while building trust and fostering technical growth in others. An important point here is to keep trying when building trust fails.
Thinking Broadly - consider how technical decisions impact the entire system ecosystem, including future scalability, maintenance costs, team dynamics, and business objectives, rather than focusing solely on immediate technical challenges.
Glue Work - excel at the often-invisible tasks that keep teams connected and projects moving—like facilitating cross-team meetings, documenting decisions, mentoring junior engineers, and resolving conflicts which are critical for organizational success but rarely appear in job descriptions or performance reviews.
Differentiators
| Principal Engineer | Senior Engineer |
|---|---|
| Provide direction to technical projects | Write code, review and maintain code quality |
| Department and company wide problem solving | Project-based problem solving |
| Mentor teams of engineers | Mentor junior engineers within their teams |
| Influence the technical culture of the company | Influence the internal decisions of their team |
| Make long-term strategic decisions | Make decisions related to their team |
| Understand multiple domains | Understand their specific domain |
References
What is a Principal Engineer Role?
Glue Work
Leadership - What is a Principal Engineer?
Principal Engineer vs Senior Engineer