There are two common ways to connect to an A2P SMS provider: SMPP, the protocol built for the telecom industry, and an HTTP API. Most wholesale providers offer both, so the SMPP vs HTTP choice depends on your volume and setup.
| SMPP | HTTP API | |
|---|---|---|
| Connection | Persistent bind over TCP | One web request per message or batch |
| Throughput | High, set in TPS per bind | Good, limited by request rate |
| Delivery reports | Returned on the same bind | Sent to your webhook |
| Setup | Needs an SMPP client and IP whitelisting | Any developer can start in minutes |
| Typical user | Carriers, aggregators, CPaaS | Applications and smaller senders |
When to choose SMPP
If you send high volumes, resell traffic or already run an SMS platform, SMPP (usually version 3.4) is the standard. Ask the provider for the number of binds and the TPS per bind.
When HTTP is enough
If you send from an application, for example OTP codes from a website, an HTTP API is simpler and usually sufficient.
When you request or offer an SMS route on VoIPMatcher, tick the connectivity you need or support. More on A2P SMS routes.
Frequently asked questions
What is the difference between SMPP and SMTP?
SMTP is the protocol for sending email between mail servers. SMPP is the protocol for exchanging SMS between applications, aggregators and operator message centres. Some SMS providers offer an email to SMS gateway that accepts messages over SMTP and converts them, but direct A2P connections at volume use SMPP or an HTTP API.
What is the difference between SMPP and SMSC?
An SMSC (Short Message Service Centre) is the operator system that stores and delivers SMS to handsets. SMPP is the protocol used to talk to an SMSC, or to an SMS platform that works like one. When you bind over SMPP to a provider, your application sends messages to their SMSC or gateway.
Is SMPP faster than an HTTP API?
For high volumes, usually yes. SMPP keeps a persistent bind open and can send many messages without waiting for each response, up to the agreed TPS and window. An HTTP API needs a web request per message or batch. For an application sending a few messages per second, the difference is rarely noticeable.
Which SMPP version should I use?
SMPP 3.4 is the version almost every SMS provider supports and the one most clients are built for. Version 5.0 exists but is rarely required in A2P. Ask the provider which version and optional parameters it supports, along with the number of binds, TPS per bind and how delivery reports are returned.
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