Ultimate Guide to Understanding SMS API

There are many SMS API available, and they all seems to do the same thing.

Tell me the number and message to send, and I will send to the phone.

A simple I/O operation it seems, but the truth is not.

Nexmo provided a guide to SMS deliverability. An excellent guide for new API users.

I also learnt a few new things.

• If you know the MCC/MNC your recipient is on (you can if you have a mobile app), then you can use Nexmo API with "network-code". This will avoid number portability problem.
• REST can scale as well as SMPP 
• Refer to their country specific guide

Standard for SMS/Network API

GSMA does have a mandate on how network APIs should be designed.

For example, this is what they mandated for SMS Restful API.

AFAIK, Simplified does follow the "rules". But does it do any good?

Free SMS API - Zeepmobile

SMS does have a cost and so a free SMS API that sends everywhere is impossible.

But Zeepmobile claims that. They have a catch of course.

Ads will be appended to the SMS send. To use an ad-free version, you have to subscribe to $9.95/month.

Zeepmobile is also not suitable to be used for SMS marketing. This is because to use the API, the users need to explicitly subscribe first. Developers are required to implement this subscription step.

Fly Letter (China 飞信) SMS API

Fly Letter (飞信) is a China telecom service.

They have an SMS API too! With that, SMS can be sent for free to China mobile subscribers!