ClickSend SMS

ClickSend is a cloud-based SMS service. It offers fast delivery times by using direct, high performance routes. The ClickSend SMS API allows users to send SMS programmatically by integrating the service into their applications, websites, or software. Possible uses include billing reminders, following up with customers, delivery notifications, and alert sending.

31Events

31Events is a calendaring service that sends invites directly to a customers' calendars. If the invite is accepted, the recipient is automatically signed up for the event. The service aims to monitor large groups along with accept or deny status and hopes to Increased Webinar attendance. The 31Events API uses REST calls, returns JSON, and allows users to make a variety of calls including create, update, get , list and delete events, as well as manipulate account information. An account is required with service.

HSL SMS

HSL (Hay Systems Ltd.) SMS provides a messaging gateway that can easily be integrated with other applications to allow them to send and receive SMS. HSL SMS is a versatile service that can be used for emergency alerts, M2M (machine-to-machine) calls, staff communications, customer promotions, two-factor authentication, and more. Integration can be accomplished using a variety of protocols, including REST, SOAP, SMPP, and SMTP.
HSL SMS

Skebby

Skebby is a cloud-based SMS service that allows users to send and receive SMS online. Developers can integrate Skebby's SMS gateway with their own website or application using its API. Calls may be issued in REST, SOAP, or SMTP format, and code examples are available in ASP, PHP, and HTML.
Skebby

fastsms

Fastsms provides cloud-based SMS services that operate over tier 1 UK network routes. Pricing for texts starts at 2.1 pence per message. Customer support is available at all times. Developers can integrate fastsms into their own applications and systems using REST, FTP/SCP, or SMTP calls.
fastsms

Way2VoiceSMS

Way2VoiceSMS provides bulk SMS services for sending messages in text, Unicode, WAP push, and long text format. Message recipients can be chosen based on their location or any other information the user has on file. Way2VoiceSMS supports polling recipients to determine public opinion. Bulk SMS can be sent and received through the website, desktop application, or API. Available API methods include SOAP, SMPP, and SMTP.
Way2VoiceSMS

SMS Ingenuity

SMS Ingenuity (SMSi) is an SMS marketing service that can be used for bulk messaging, birthday reminders, timed campaigns, one-on-one communications, text-to-vote campaigns, and recurring messages. SMSi comes with features for automatically personalizing messages, managing contacts, and creating message templates. Developers can integrate the SMSi messaging gateway into their own application using the SMSi API. This allows them to send SMS programmatically using a wide variety of protocols and methods.
SMS Ingenuity

SMSCluster

SMSCluster is an international SMS marketing service that enables users to send bulk SMS to recipients anywhere in the world. It can be used to send alerts, run a marketing campaign, celebrate an event, and perform other mass communication tasks. During development, users can make use of a "simulation mode" to avoid wasting funds on sending test SMS. The SMSCluster API allows users to send and receive messages as well as check the status of sent messages via REST, SMTP, or SOAP calls. Users can send up to 10,000 texts with a single API request. SMSCluster provides free sample scripts for its API in Java, Ruby, PHP, Python, Perl, and (in the near future) C#.
SMSCluster

Channel Mobile SMS

Channel Mobile is a South African mobile marketing agency that enables users to send out targeted advertisements in the form of SMS, MMS, and USSD. Messages can be set up to send automatically when specific events occur. Developers can integrate their systems with Channel Mobile's SMS gateway using XML strings sent over REST, SMPP, or SMTP protocols.
Channel Mobile SMS

PageOne

PageOne is a company that provides mobile communication solutions to organizations throughout the UK. Their SOAP API allows users to enable their applications to send and receive SMS in over 300 countries. The API supports text, binary SMS, and flash messaging and provides delivery acknowledgement after sending. It can also handle location-specific functions like targeting recipients in a given area, providing local information, and tracking resources or equipment. Additional methods of connecting to PageOne's messaging gateway include REST, SMPP, SMTP, and SCP.
PageOne