Index · Cert expiry · Fastest sites · Free tools · API
20 popular education sites, ranked by security-header score. Live data, built 2026-11-01.
| # | Site | Headers | Score | Cert days | Avail | ms |
|---|---|---|---|---|---|---|
| 1 | stanford.edu | A | 100 | 5 | 100% | 162.5 |
| 2 | ox.ac.uk | A | 100 | 64 | 100% | 567.1 |
| 3 | cam.ac.uk | A | 100 | 53 | 100% | 103.1 |
| 4 | berkeley.edu | B | 83 | 69 | 100% | 35.5 |
| 5 | edx.org | B | 83 | 173 | 100% | 122.2 |
| 6 | udemy.com | B | 83 | 71 | 100% | 24.7 |
| 7 | udacity.com | B | 83 | 93 | 100% | 147.3 |
| 8 | w3schools.com | B | 83 | 119 | 100% | 1050.3 |
| 9 | freecodecamp.org | B | 83 | 72 | 100% | 430.0 |
| 10 | pluralsight.com | C | 67 | 66 | 100% | 570.3 |
| 11 | theodinproject.com | C | 67 | 74 | 100% | 485.1 |
| 12 | exercism.org | C | 67 | 74 | 100% | 51.8 |
| 13 | mit.edu | C | 50 | 12 | 100% | 627.6 |
| 14 | coursera.org | C | 50 | 127 | 100% | 621.5 |
| 15 | brilliant.org | D | 33 | 43 | 100% | 210.6 |
| 16 | duolingo.com | F | 17 | 191 | 100% | 431.4 |
| 17 | codecademy.com | F | 17 | 84 | 100% | 341.5 |
| 18 | harvard.edu | F | 0 | 38 | 100% | 37.7 |
| 19 | khanacademy.org | F | 0 | 177 | 100% | 39.5 |
| 20 | scrimba.com | F | 0 | 63 | 100% | 194.3 |