What Makes a Great Senior+ Engineer? Looking for Concrete Examples

I asked my perplexity space and it combed through the entirety of taro to find case studies. Here is the response. Please check for inaccuracies but overall initial skim looks pretty solid. Reason I used AI was because its particularly great at these kinds of tasks of skimming large amounts of data and pulling it together! Hopefully others can provide more insights here

Great Senior+ engineers combine technical depth with strategic influence, focusing on multiplier effects that elevate entire teams and systems. Here’s a breakdown of key traits and case studies from the provided sources:

Ownership of High-Impact Goals

Staff+ engineers own outcomes beyond individual projects. For example:

- Portal Video Calling Reliability at Meta: A Staff Engineer led a team-wide initiative to reduce video call drops by 5% through systematic fixes. This involved diagnosing environmental factors (e.g., Wi-Fi instability), creating automated detection tools, and improving user messaging during failures. The project required coordinating with infrastructure teams and mentoring senior engineers to delegate components like retry logic and health checks[^3].

- Internal Debugging Tool at Meta: An engineer built a tool for their team to debug a specific class of issues. Over time, it scaled organically to hundreds of engineers across the org, reducing debugging time by 30% and becoming a critical part of the developer workflow[^3].

Creating Scope Through Systems Thinking

Staff+ engineers build infrastructure that unlocks team productivity:

- Binary Size Automation: A Staff Engineer at a large tech company automated detection of APK size regressions. Instead of manually fixing issues, they integrated checks into CI/CD pipelines, leaving contextual feedback on code changes and linking playbooks for resolution. This reduced recurring issues by 70%[^3].

- On-Call Overhaul at Instagram: An engineer redesigned the on-call process by analyzing root causes of past incidents, creating runbooks, and implementing SLAs. This cut alert fatigue by 50% and improved cross-team escalation protocols[^3].

Cross-Team Influence and Roadmap Leadership

Staff+ engineers shape direction beyond their immediate team:

- Meta’s Cross-Org Collaboration: A Staff Engineer working on real-time video infrastructure became the “first customer” of a new internal system. They partnered closely with infra teams to ensure compatibility with future use cases, influencing the roadmap of 5+ teams[^3].

- Generative AI Integration at Google: A Staff Engineer in Search identified generative AI as a strategic priority. They convinced leadership to allocate resources by tying it to core metrics (e.g., query resolution rate), then led a cross-functional team to prototype integrations[^3].

Fixing Systemic Issues (The “Fixer” Archetype)

Staff+ engineers solve problems others can’t:

- \$10M Cost-Saving Debugging: An engineer at Meta traced sporadic performance degradation across 5 teams to an overlooked interface issue. By refactoring the system, they saved \$10M annually in cloud costs[^3].

- Spaghetti Code Rescue: At a startup, a Staff Engineer untangled a mission-critical but poorly documented codebase. They identified a core race condition bug, leading to a 10% KPI improvement in user engagement[^3].

Mentorship as a Force Multiplier

Staff+ engineers raise leaders, not just contributors:

- Meta’s L5 Mentorship Program: A Staff Engineer created a “consultative” mentorship model for senior engineers. Instead of tactical debugging help, they taught L5s to diagnose systemic issues (e.g., API latency patterns) and advocate for org-wide fixes. This led to 3 promo-ready L5s within a year[^3].

- On-Call Training Initiative: At Robinhood, a Staff Engineer developed a rotation program that paired juniors with seniors during incidents. Postmortem ownership was delegated to L4s, accelerating their growth and reducing escalations by 40%[^3].

Key Mindset Shifts

1. From “My Code” to “Our Systems”: Staff+ engineers optimize plumbing (CI/CD, observability) over individual features[^3].

2. Questioning the Map: They challenge assumptions (“Why are we optimizing X?”) and align work to business KPIs[^3].

3. Playing the Long Game: Building trust over 2+ years is critical for promotions, as seen in Meta’s anti-Peter Principle culture[^3].

For those aiming for Staff+, focus on archetypes that match your strengths: Fixer, Specialist, or Product Hybrid[^3][16-18]. Use frameworks like 30-60-90 day plans to align with manager expectations early in new roles[^1].

[^1]: https://www.jointaro.com/question/6Vxacep9fTMaFCtYJxU6/how-can-i-be-an-effective-senior-engineer-on-my-new-team/

[^2]: https://www.jointaro.com/topic/staff-engineer/

[^3]: https://www.jointaro.com/course/grow-from-senior-to-staff-engineer-l5-to-l6/

The best senior+ engineers that I've worked can do the following:

1. Identify the best problems to work on
2. Go through the work of scoping out the problem
3. Create buy-in from different stakeholders to agree on the problem
4. Carry out the solution end to end, usually by delegating the work across many engineers on different teams

And, they are able to juggle multiple of these projects at the same time