The short answer
- Use SOAP when the system that triggers the message already calls SOAP web services and changing that is costly or slow.
- Use REST for new applications, websites and mobile back ends: it works from almost any language.
- Use SMPP when you send sustained, high volumes of SMS and can keep a long-running connection open.
- Whatever you choose, your servers connect from whitelisted IP addresses or over a VPN connection, your SMS sender name must be registered, and Arabic text uses more SMS segments than English.
What SOAP is, in one paragraph
SOAP is a W3C standard for exchanging structured information between systems as XML. Each SOAP message is an envelope with an optional header, for control information, and a mandatory body, which carries the request itself. When a request expects a response over HTTP, the SOAP message travels as the payload of a POST request. If an established system already calls other services through SOAP, SOAP can be the shortest route from that system to SMS.
SOAP, REST or SMPP: which interface for which system
| SOAP | REST | SMPP | |
|---|---|---|---|
| Message format | XML envelope | HTTPS requests, usually with JSON | Binary protocol over a persistent session |
| Connection | Request and response per call | Request and response per call | Long-running session your system keeps open |
| Typical fit | ERP, billing and established enterprise systems that already call SOAP services | New applications, websites, mobile back ends, CRM workflows | Sustained high-volume SMS; telecom-oriented systems |
| What your team needs | The system's SOAP client or connector; XML mapping | Any HTTP library | An SMPP client and the skills to run a persistent session |
Ask us which operations each interface supports for your account before you design the integration.
If one organisation has several systems, they do not all have to use the same interface. One possible pattern is SOAP from the ERP for invoices and payment reminders, REST from the app for passcodes and order updates, and SMPP only where volume justifies it.
REST or SMPP: a detailed comparison
Before the first message: what to prepare
- List the systems that will send, and which messages each one triggers: passcodes, alerts, reminders, campaigns.
- Choose an interface per system using the table above.
- Give us the outbound IP addresses of the servers that will call the API, for test and production, so they can be whitelisted, or arrange a VPN connection.
- Register your SMS sender names. Interkey registers them with the regulator and the operators during onboarding.
- Prepare templates for the messages your team sends from the platform. Templates are approved by your team and by Interkey before use.
- Check Arabic message length. An Arabic SMS holds 70 characters in a single message and 67 per segment when it is longer; English (GSM-7) holds 160, or 153 per segment.
- Decide how your system will learn the delivery result of each message, and what it does when a message fails.
- Agree a test plan: a small set of real numbers on each Saudi network, in Arabic and English.
Questions to ask about any SOAP SMS interface
- Which operations are available over SOAP: single send, batch send, delivery status?
- How is a request authenticated, and how are credentials replaced?
- How does your system get delivery results: by asking for status, or by receiving a callback?
- Is there a service description your SOAP client can import, and a test environment?
- What happens when a request is rejected, and which error codes come back?
We answer these in writing for your account during integration planning.
How Digital Connect fits
- Three interfaces on one platform: REST for application traffic, SMPP for sustained high-volume SMS, and SOAP where an existing business system requires it.
- CRM and ERP integration support.
- Access controls: whitelisted IP access or a VPN connection for your systems; two-factor login with a verification code sent by email, and admin and user permission levels, for platform users.
- Account protection: fraud protection, country blocking and spending limits.
- A delivery receipt for each message, and one set of delivery reporting.
- Sender name registration with the regulator and the operators, handled during onboarding.
- Support from Riyadh on the Saudi working week, in Arabic and English.
- Pricing is quoted for your volumes.
When it is not a good fit: if almost all of your recipients are outside Saudi Arabia, or you send only a few hundred messages a month.
Security and access controls in Digital Connect
Questions integration teams ask
Is SOAP slower or less reliable than REST?
A SOAP request carries more markup than a typical REST request, because of the XML envelope. Both are request-and-response calls over HTTP, so choose the interface your system can build and maintain most easily, and use SMPP where sustained volume justifies it.
Can our system see the delivery result of each message?
Yes. Digital Connect provides a delivery receipt for each message. Ask us how your system receives it over the interface you choose.
Our ERP has no SOAP connector. What then?
Use REST from a small integration service or your existing middleware, or ask your ERP partner whether a connector exists. We can review the options with your team.
Which IP addresses do we need to whitelist?
The outbound addresses of every server that will call the API, in test and in production. Plan this before go-live, because a new server or a changed address has to be added to the whitelist. If a fixed address list is hard to keep, ask about a VPN connection instead.
Can different systems use different interfaces on the same account?
Ask us for your setup. Planning one interface per system is often simpler than forcing every system onto one.