The Principal Engineer Track

Short, self-contained lessons, beginner→advanced at the staff+ level. Each lesson teaches one idea tied to the mission — be genuinely ready for the Principal move in three months — and every lab produces a real artifact (an ADR, a design doc, an SLO worksheet, a strategy memo) that works as both promotion evidence and interview material. Built on high-trust sources: Will Larson and Tanya Reilly on the staff+ role, Kleppmann on data systems, Richards & Ford on architecture, Rumelt on strategy, and the Google SRE book on operating at scale.

Lessons

Module 1 · The Principal Mindset · Beginner

• Lesson 01 What a Principal Engineer Actually Does The senior→staff+ delta, the four archetypes, glue work — and your first artifact: a scope map of where you already fit.
• Lesson 02 Thinking in Trade-offs The core mental move of the level: no best answers, only least-worst trade-offs you can defend — the two laws, hidden costs in "best practices", and your first trade-off table.

Module 2 · Architecture & System Design · Intermediate

• Lesson 03 Reading a System Like a Principal The five reads that build an accurate mental model of any unfamiliar system — data flow, boundaries, failure modes with blast radius, the bottleneck, and the assumptions nobody is checking.
• Lesson 04 Distributed Systems Intuition Replication, partitioning, consistency, and why consensus is hard — no-math mental models that turn "weird bugs at scale" into named mechanisms with known mitigations.
• Lesson 05 ADRs & Design Reviews Decisions are your output — capture them in one-page ADRs with honest consequences, and stress-test them in design reviews that ask questions instead of issuing verdicts.
• Lesson 06 The System Design Lab Module 2's capstone lab: a full two-page design doc for TicketFlow — a 2M-tickets/day support platform — with estimation, an ADR, a failure-mode table, and a Principal-level review or mock interview.

Module 3 · Operating at Scale · Intermediate

• Lesson 07 SLOs & Error Budgets Reliability as a product decision: SLIs, SLOs, and the error budget that turns "is it reliable enough?" into arithmetic — plus an SLO worksheet for a real service.
• Lesson 08 Incident Leadership Command an incident without touching a keyboard — the Incident Commander model, severity as decision rules, and the blameless postmortem as org-level leverage.
• Lesson 09 Observability, Performance & Cost Monitoring answers known questions; observability answers unknown ones. p99 over averages, and cloud cost as a trade-off column — plus an operability audit of a real service.

Module 4 · Technical Strategy & Vision · Advanced

• Lesson 10 Writing Technical Strategy Rumelt's kernel — diagnosis, guiding policy, coherent action — applied to engineering, plus Larson's write-five-then-synthesize method. Lab: a one-page strategy memo for your real area.
• Lesson 11 Build-vs-Buy & Platform Thinking Three questions — does it differentiate, what does it really cost, which door is it — plus when shared platforms pay and when they're a tax.

Module 5 · The Move Itself · Advanced

• Lesson 12 The Promotion Packet & the Interview Loop Turn eleven lessons of artifacts into the move itself — a promo packet your sponsor can fire, and interview stories that land at Principal depth.
• Lesson 13 Capstone: Operate at Principal Level Diagnose, architect, and operationalize "Meridian" end to end — a three-artifact portfolio graded against a Principal-level rubric, with a skeptical-CTO and mock-interview feedback loop.

Reference

• Living document Glossary The canonical vocabulary for the course — archetypes, glue work, ADRs, SLOs, the strategy kernel. Every lesson uses these terms exactly.
• Printable · Lesson 05 ADR Template Copyable ADR template (Nygard format + alternatives), a worked example, and the six-item good-ADR checklist.
• Printable · Lesson 07 SLO Cheat Sheet SLI vs SLO vs SLA, the SLI menu, the nines table, error-budget math in one worked example, and five SLO-setting pitfalls.
• Printable · Lesson 10 The Strategy Kernel Rumelt's kernel with one-line tests, the four bad-strategy tells, Larson's write-five recipe, and a strategy-doc review checklist.
• Printable · Lesson 12 Promotion Packet Checklist Packet skeleton, the artifact→claim map for all ten course artifacts, five evidence-quality tests, and the interview-story worksheet.