SMS APIs
Trigger SMS from your application- Bulk SMS Gateway
- Web SMS Platform
- Email to SMS
- SMS Replies
- SMS APIs
- Dedicated Short Codes
- Keyword Campaigns
- AU Long Codes
- How to receive SMS
One flexible HTTP API for sending SMS
SMS4U now recommends the Flexi API for new SMS integrations. It is a flexible HTTP endpoint that accepts common JSON schemas and field names, then maps them into a valid SMS message request.
This makes it useful when connecting CRMs, forms, automation platforms, monitoring tools, existing SMS integrations, or custom applications that already produce SMS-style payloads.
Example payload
Use simple, familiar fields such as to, from, and body, or use alternate names from an existing system.
JSON request bodyapplication/json
{
"to": "+6421000001",
"from": "5555",
"body": "Hello, this is a test."
}The Developers page includes endpoint details, callback examples, response handling, and webhook payload examples.
Accepts common schemasUse common names such as
to, mobile, destination, message, body, and content.Built for migrationsPoint an existing SMS-style JSON workflow at SMS4U without needing to rewrite every field name first.
Supports result and inbound webhooksReceive delivery results and inbound SMS replies back into your application, CRM, helpdesk, or workflow automation system.
Need implementation details?
The full Developers page covers the Flexi API endpoint, accepted field aliases, JSON examples, response statuses, result webhooks, and inbound SMS webhooks.