Specimen III · 05
CS50 / edX Harvard
free
Canonical CS intro, CS50-issued cert free
7.1M enrollments. Free cert available from CS50 directly (edX verified cert is paid).
| Habitat | Learning |
| Access tier | free |
| Relevance to stack | medium |
| Last active signal | CS50x 2026 refresh with AI section |
| Verified alive | yes — pressed 2026 |
| Specimen no. | III · 05 |
| Live habitat | https://cs50.harvard.edu/x |