How this series works
How this series works
90 Days of X is a series of independent volumes, not one course you must take as a bundle. Each volume (sub-book) is a self-contained, expert-ordered path of roughly ninety study days. You choose which volume to follow and how to fit it into your life.
Core ideas
- Volumes are separate. Finishing Go does not require NixOS (or any future volume), and the reverse is also true.
- One volume at a time is the normal mode. Studying two volumes in the same period is optional and entirely your decision—not a requirement of this resource.
- Expert order inside each volume. Day numbers are pacing guides; gates matter more than dates.
- Syllabus first. Narrative chapters are written against each volume’s syllabus contract.
- The series can grow. A successful volume → add another (Rust, Kubernetes, …) without rewriting existing ones.
What a volume contains
| Piece | Purpose |
|---|---|
| Overview | Audience, baseline versions, “done” criteria, optional links to other volumes |
| Syllabus | Stages, days, gates, explicit out-of-scope |
| Chapters | Mental model → examples → labs → gotchas |
Quality bar (every volume)
- Prefer official docs over stale blogs when they conflict
- Ship artifacts (repos, flakes, services), not only notes
- End with a capstone that proves integration
- No certification branding unless a volume deliberately adds exam prep later
Optional cross-volume links
Some topics can connect later in your own study plan (for example: implement a tool in Go, then package it with Nix). Those are your bridges—not schedules and not dependencies in this series. This series does not hyperlink out to other monorepo books.
Success for a single volume
You succeed when that volume’s overview checklist and capstone hold—regardless of whether you ever open another volume in the series.