KalSMS SMS/MMS gateway for Android

About

KalSMS is a SMS/MMS gateway running entirely as an Android app.

It enables web services to send and receive SMS/MMS messages by forwarding incoming messages to a server on the Internet, and sending outgoing messages to other phones.

People with any type of mobile phone can send SMS/MMS to a phone running KalSMS, without needing their own Android phone.

It works wherever the phone can receive SMS messages and access the Internet (via Wi-Fi or mobile data connection).

Why KalSMS?

KalSMS can be used nearly anywhere in the world. In particular, it is useful in countries where obtaining a local virtual phone number or SMS shortcode is difficult, expensive, or impossible. A phone running KalSMS connects to the phone network in the same way as any other mobile phone, so it can be set up without needing approval from anyone else.

KalSMS is designed to to be maintainable even when deployed in remote locations that cannot easily be accessed by your organization's technical staff. KalSMS is simple enough for non-technical users to do all setup and maintenance of deployed phones.

Price

The KalSMS app itself is free to install on as many phones as you'd like.

In order to deploy KalSMS, the only monetary costs are the cost of a messaging plan for your phone, and the price of the phone itself. KalSMS is compatible with many old or inexpensive Android phones, e.g. the LG GT540, currently $120 on Amazon.com.

Typically your organization will need only one phone running KalSMS in a particular country, although you could have multiple phones to load-balance requests for higher throughput, to offer different user services, or to serve different mobile networks.

Comparison to Alternative Methods

SMS gateways can be created using several alternative methods, including hosted services (e.g. Twilio, Tropo, Clickatell), connecting GSM phones/modems to a computer (e.g. FrontlineSMS, RapidSMS, Kannel), and partnering directly with mobile operators.

	Benefits	Drawbacks
Hosted services	High message throughput Easy to deploy	No local numbers in many countries Usually no MMS support
Connecting modem to computer	Can work with inexpensive phone	Expensive hardware costs Lots of moving parts to keep working Very difficult for non-technical users to deploy Low message throughput No MMS support
Partnering with Mobile Operators	High message throughput Can provide free service to users via shortcode	Usually very expensive Requires operator approval Long setup time

KalSMS is ideal for situations where no hosted services with local numbers are available in a particular country, or when it is necessary to receive MMS messages. KalSMS likelly has lower throughput than hosted services or partnering with mobile operators, but should be able to forward up to a few thousand messages per phone per day.

Contributors