Integration typeWHMCS hooks + REST API
ZendSMS integration guide
WHMCS hooks + REST APIConnect WHMCS billing events to SMS.
Send invoice, payment, service, renewal and support notifications from selected WHMCS hooks through ZendSMS.
WHMCSBusiness event
ZendSMS202 QUEUEDYOURBRAND
Invoice #2048 is due on 18 September. Please review your account.
✓ DeliveredSecurity patternServer-side only
Response202 Accepted + message_id
Common workflows
What you can send from WHMCS.
Turn important billing and service events into timely customer messages.
Invoice reminders
Notify clients before or after an invoice due date.
Payment confirmation
Confirm successful payments with a clear reference.
Service lifecycle
Send activation, suspension or renewal notices from approved hooks.
Support alerts
Notify customers or staff about selected ticket events.
Verified API pattern
From one business event to one trackable SMS.
This request uses the fields in the current ZendSMS Send SMS reference. Keep the API key in a secret store, attach a unique client_ref and save the message_id from the accepted response.
- 01
Define the workflow
Choose the event, recipient and message that should be sent.
- 02
Connect securely
Keep the API key on the server and make the request over HTTPS.
- 03
Map the template
Map the approved sender ID, recipient, message and client reference.
- 04
Test and launch
Check the result, segment count and delivery state before production.
POST /api/v1/send-sms202
Authorization: Bearer sk_your_api_key
{
"recipient": "8801700000000",
"sender_id": "YOURBRAND",
"message": "Invoice #2048 is due on 18 September. Please review your account.",
"client_ref": "invoice-2048"
}success: truestatus: QUEUEDmessage_id: UUID
Read the complete Send SMS reference Included in the workflow
Build a production-ready flow, not just a send button.
Event-driven SMS
Send only when a selected business event occurs.
Every core SMS type
Use OTP, Masking or Non-Masking SMS for the approved use case.
References you can track
Keep your own client reference and the returned message ID.
Bangla and Unicode
Send Bangla, English or Unicode content for the customer journey.
WHMCS FAQ
Answers to review before production.
A concise guide to security, SMS types, delivery reconciliation and testing.
Should the WHMCS integration call the API from a browser?
No. A secret API key must never be placed in browser code or public JavaScript. Send requests from a trusted server, backend function or protected connector.
Which SMS types can WHMCS send?
You can use OTP, Masking and Non-Masking SMS for an approved use case. Sender ID and template activation remain subject to KYC, documents and applicable operator or regulatory approval.
How do I reconcile delivery results?
Attach a unique client_ref to each request and store the message_id returned in the accepted response. Reconcile delivery status using the current API documentation.
What should be tested before launch?
Test event mapping, recipient format, Bangla/Unicode segments, duplicate prevention, error handling and delivery results. Complete consent and compliance review before production.
Related integrations
Explore another path for the same workflow.
Ready to connect?