Everything worth knowing, nothing that isn't.
The request
BroadNet's gateway accepts a POST to https://api.broadnet.me/sms/sendSms with an Authorization: Bearer token and a JSON body: senderId (the sender ID), destinationNumber (the destination number in international format, digits only, no plus sign), message (the text), and messageType (TEXT for GSM-7, UNICODE for Arabic, emoji and other non-Latin scripts). A successful call returns 200 OK with the message ID in the response body.
Encoding and length
A GSM-7 message fits 160 characters per segment (153 once a message spans multiple segments); switching to Unicode for emoji or non-Latin scripts drops that to 70 (67 concatenated). Set messageType to TEXT for plain GSM-7 and UNICODE when the body needs Unicode or Arabic, so characters aren't garbled — POST /sms/identify returns the encoding and segment count before you send.
Track delivery, don't assume it
The returned message ID is the handle for delivery receipts (DLRs). Configure a webhook to receive the operator's final status — delivered, failed, or expired — rather than treating a 200 on submission as proof the handset received the message.
Moving to production
Use international E.164 numbers, register your sender ID in each destination market before you scale, and send over direct operator routes for consistent latency. For high volume the same account is reachable over SMPP as well as REST, so you can start on HTTP and switch bind types without re-onboarding.