Specimen VI · 03
System Design Primer
free
Canonical free system design reference
296 open PRs backlog but base content remains the free canon. Anki flashcards included.
| Habitat | Interview prep |
| Access tier | free |
| Relevance to stack | medium |
| Last active signal | Merges slow but content authoritative |
| Verified alive | yes — pressed 2026 |
| Specimen no. | VI · 03 |
| Live habitat | https://github.com/donnemartin/system-design-primer |