The best C# SMS API in 2025
In 2025 it is not easy to find the best C# SMS API. You may have different needs depending on the project, and it is important to pick the option that best fits your needs. This document gives information about the options you can choose form and highlights the drawbacks and benefits of each option.
C# SMS API client
The C# SMS API client is best if you develop a desktop or mobile client application, that runs over a considerable amount of time. This solution creates a connection to the SMS gateway, and keeps this connection option, to make sure you receive SMS messages in real time. It is also great, because no connection overhead happens when you try to send an SMS, plus you get instant notification about SMS delivery events, such as SMS submit reports and SMS delivery reports.
Learn more: C# SMS API client with full source code
The C# SMS API client is best if you develop a desktop or mobile client application, that runs over a considerable amount of time. This solution creates a connection to the SMS gateway, and keeps this connection option, to make sure you receive SMS messages in real time. It is also great, because no connection overhead happens when you try to send an SMS, plus you get instant notification about SMS delivery events, such as SMS submit reports and SMS delivery reports.
Learn more: C# SMS API client with full source code
Simple C# SMS script
If you want to send a reply SMS through a C# SMS API, it means that you are developing an autoresponder application. You C# app will create some kind of logic to answer each incoming SMS message. If the logic is simple, your best option could be not to develop a fully featured SMS solution and host it at a webserver or in windows service. It might be a great choice to simply write your logic in C# and let Ozeki SMS gateway do the execution. When you use this approach, you simple copy paste your script into the SMS gateway.
Learn more: C# SMS script to reply SMS messages
If you want to send a reply SMS through a C# SMS API, it means that you are developing an autoresponder application. You C# app will create some kind of logic to answer each incoming SMS message. If the logic is simple, your best option could be not to develop a fully featured SMS solution and host it at a webserver or in windows service. It might be a great choice to simply write your logic in C# and let Ozeki SMS gateway do the execution. When you use this approach, you simple copy paste your script into the SMS gateway.
Learn more: C# SMS script to reply SMS messages
C# SMS messaging using HTTP requests
The C# HTTP api is a good option for ASP.Net and other website backend solutions. It sends an SMS messages using a fire and forget HTTP request. This is beneficial when serving websites, because server-side scripts tend to live only for a short time while the served webpage is constructed. This short period does not tolerate a long time wait for SMS submit reports and sms delivery reports to be returned. Issuing HTTP requests is a natural way to interact with the Ozeki SMS gateway in these systems.
Learn more: How to send SMS from C# using an SQL database
The C# HTTP api is a good option for ASP.Net and other website backend solutions. It sends an SMS messages using a fire and forget HTTP request. This is beneficial when serving websites, because server-side scripts tend to live only for a short time while the served webpage is constructed. This short period does not tolerate a long time wait for SMS submit reports and sms delivery reports to be returned. Issuing HTTP requests is a natural way to interact with the Ozeki SMS gateway in these systems.
Learn more: How to send SMS from C# using an SQL database
C# SMS messaging using MS SQL
If you write a business application, that works with data stored in a database server, or you work with several thousand (or million) SMS messages, your best option is to send and receive SMS from C# SMS using an SQL database. In this case you would setup two database tables: one for sending SMS and another for receiving SMS messages. Your C# application would put the SMS messages you wish to send into to outbox table, and the SMS gateway will pick it up from there and deliver them. Incoming messages will be inserted by the SMS gateway in the inbox table. The great thing about this solution is that the SMS gateway will update delivery timestamps and messages status information, so you will know whether and when your SMS was sent and received by the recipient without writing any code.
Learn more: How to send SMS from C# using an SQL database
If you write a business application, that works with data stored in a database server, or you work with several thousand (or million) SMS messages, your best option is to send and receive SMS from C# SMS using an SQL database. In this case you would setup two database tables: one for sending SMS and another for receiving SMS messages. Your C# application would put the SMS messages you wish to send into to outbox table, and the SMS gateway will pick it up from there and deliver them. Incoming messages will be inserted by the SMS gateway in the inbox table. The great thing about this solution is that the SMS gateway will update delivery timestamps and messages status information, so you will know whether and when your SMS was sent and received by the recipient without writing any code.
Learn more: How to send SMS from C# using an SQL database
More information