Kerna vs thread.
| Kerna | thread. | |
|---|---|---|
| Free plan | Yes | Yes |
| Free trial | No | No |
| Paid from | €12/mo | Free |
| Open source | No | No |
| Platforms | macOS, Web, Windows | — |
| Free plan | Yes | Yes |
| Tone controls | Yes | Yes |
| Custom instructions | Yes | Yes |
| Email context input | thread | thread |
| Browser extension | No | Yes |
| Mail client support | both | both |
| Supported languages | 45 languages | — |
Both are listed in Best AI Email Writing Tools. On Samsung Mobile US Press, Kerna scores higher on our published basis.