| Price from | €599/mo | — |
| Free plan | — | — |
| Free trial | Yes | Yes |
| Open source | — | — |
| Web | Yes | Yes |
| iOS | Yes | — |
| Android | Yes | — |
| API | Yes | Yes |
| Plans published | 2 | 6 |
| Spec score · Transactional SMS Software | 9.1 (#3) | 7.7 (#41) |
| Headquarters | Paris and New York | Paphos, Cyprus |
| Integrations | Callr lists native connectors for Salesforce, HubSpot, Google Analytics, and Google Ads, plus a REST API and webhooks. | The integrations page lists Zapier, Salesforce, SMS API, SMPP API, and email-based integration among its options. |
| Product | Callr provides an API-first voice and messaging platform with programmable voice, SMS, call tracking, and conversation AI. | SMS.to describes itself as an SMS marketing and SMS API gateway platform providing omnichannel digital communication services for businesses. |
| Security | Callr states that HTTPS, SIP TLS and SRTP encryption are included across plans. | Intergo Telecom says it has adopted an Information Security Management System in accordance with ISO 27001:2022. |
| Support | Callr describes 24/7 support as part of its service and lists premium customer support for Enterprise. | The homepage advertises 24/7 support and worldwide coverage. |
