You and your customers, one SMS apart

From confirmations and authentication to important updates, customers want to know constantly what is happening. Calisero delivers transactional SMS instantly, through a stable API and tools built for real-time visibility and control.

Try for free now

No obligation. Includes €1 test credit.

Communicate anything
with your customers

Notify customers or partners the moment an invoice is issued. The SMS can carry the invoice number, the amount or the due date.
Announce dispatch, hand-over to the courier and delivery, with the tracking number included in the message.
Send one-time codes for sign-in and for confirming sensitive actions, on routes reserved for time-critical traffic.
Announce incidents, service interruptions or account changes, the moment they happen.
Confirm a booking and send a reminder before it, so fewer appointments are missed.
CALISERO

Friday, 22 May

Invoice CMMS-1234 for 743.00 RON was issued on 07.07.2025. Please pay it by 17.07.2025. Details in your customer account.
10:47

Benefits you can trust

Instant delivery

Messages reach recipients in seconds, with guaranteed dispatch and a high delivery rate.

Cost control

Full control over costs thanks to transparent pricing, no hidden fees, with detailed billing reports.

Detailed reports

Access detailed reports for every message: delivery status, errors and real-time analytics.

Free testing

Try the platform with a free account — test every feature before commercial use.

Guaranteed dispatch

Guaranteed dispatch with secure routing and fallback mechanisms for maximum reliability.

Advanced debugging

Advanced debugging tools for developers: message logs, error details and real-time monitoring.

Try for free now

No obligation. Includes €1 test credit.

Send SMS fast

A robust API, detailed documentation, access to debugging information and excellent support make Calisero a partner you can rely on to grow your business.

curl -X POST 'https://rest.calisero.ro/api/v1/messages' \
  -H 'Accept: application/json' \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer {token}' \
  -d '{
    "recipient": "+4075027**27",
    "body": "Your message here",
    "schedule_at": "2024-11-16 13:21:00",
    "callback_url": "https://yoursite.ro/your-callback-url",
    "sender": "CALISERO"
  }'

Easy debugging

Access to every API request and response

Sandbox

A sandbox is available to test your integration

Documentation

Well-crafted API documentation with examples

Excellent support

Get in touch and we will be glad to help

An SMS platform built for developers

Focus on your product and leave the communication to us. Our platform offers a stable API, instant delivery and every tool you need for monitoring and troubleshooting.

  • Fast and reliable message delivery
  • Robust REST API with clear documentation
  • Real-time delivery reports and detailed logs
  • Advanced debugging tools for developers
  • Easy integration in any programming language
Documentation Integrations
Calisero dashboard 
{
  "data": {
    "id": "0197e8c5-2c11-72cf-8057-bca8f619bd52",
    "body": "Va reamintim de programarea dvs. pentru maine, 20.07.2024, ora 13:00.",
    "parts": 1,
    "sender": "CALISERO",
    "status": "scheduled",
    "sent_at": null,
    "recipient": "+40700***900",
    "created_at": "2025-07-08T06:42:05.000000Z",
    "callback_url": "https://dlr.calisero.ro/callback/e506bbe-eff4-49d6",
    "delivered_at": null,
    "scheduled_at": "2025-07-08T06:42:05.000000Z"
  }
}

Ready to try Calisero free?

Create an account and get €1 test credit, with no obligation.

Try it now