Defaults.Exposed › Compare › .io vs .dev
.io vs .dev: which is more secure?
We graded 823,855 .io domains and 502,346 .dev domains across 34 checks. Data as of 2026-06-27.
.io comes out ahead. 78.2% of .io domains score grade F (effectively unprotected — can be email-spoofed), versus 83% of .dev — a 4.8-point gap. But both leave the clear majority exposed.
| TLD | Domains graded | Grade F (exposed) | Grade A–B (secure) |
|---|---|---|---|
| .io | 823,855 | 78.2% | 1.4% |
| .dev | 502,346 | 83% | 1% |
Here's the thing: your domain's security depends on how it is configured, not which ending you picked — even the stronger TLD here leaves most of its domains at grade F. The good news is that almost every problem is free and quick to fix.
Whatever your domain ends in, check it free → and see your grade across all 34 checks (private — only you ever see it).