Alert21 vs Clickatell SMS API
| Alert21 | Clickatell SMS API | |
|---|---|---|
| Free plan | No | Yes |
| Free trial | No | Yes |
| Paid from | — | Free |
| Open source | No | No |
| Platforms | Web | api, Web |
| Pay-as-you-go | Yes | — |
| SMS API | Yes | — |
| Delivery status | Yes | — |
| Webhooks | Yes | — |
Both are listed in Best Transactional SMS Software. On Freedom251, Clickatell SMS API scores higher on our published basis.