Features You Care About

When choosing to work with a mobile messaging provider, you want to look for capabilities above and beyond the basic ability to send messages. Here are several essential capabilities OpenMarket supports: 

Global one-way and two-way messaging

With our Global SMS APIs you can send messages globally (one-way messaging), and in many regions you can also receive messages back (two-way messaging). For more information on the types of messages you can send, see one-way and two-way messaging.

One-way messaging

If your plan is to only send (but not receive) messages, you will use one-way messaging. Different mobile operators and geographic regions have their own behavior around one-way messaging. Things to know are:

  • Alphanumeric originators

    In many countries (including the UK) you can set an alphanumeric string as the message originator. This can allow you to brand the message as being from your company; e.g. "ACME SHOES". End users cannot send a reply to an alphanumeric string.

  • Changing message originators

    In some regions when sending using one-way, the mobile operator will change the message originator you've sent to a number of their choosing. This means that, if you do wish end users to potentially respond, it is important to label the message as two-way.

  • Cost-effectiveness

    In some cases, one-way messages can be more cost-effective. Consult with your OpenMarket account manager for guidance.

Two-way messaging

Use two-way messaging when you want to enable end users to reply to your message. Two-way messaging requires you to provision a short code or virtual mobile number (VMN) that can receive messages.

For a list of the countries where you can use two-way messaging, see Global Coverage Map.

Note: All messaging in the US and Canada is two-way, regardless of whether you wish to receive responses. This is a regulatory requirement; the industry in these regions require you to send messages from a provisioned, text-enabled number.

  • Short codes

    Short codes are always regional (normally national), which means messages sent to end users outside the specific region will not be able to respond.

  • Virtual mobile numbers (VMNs)

    VMNs are provisioned to receive messages within their own country or region but are internationally accessible. This means you can receive texts from end users located outside of the current country boundaries, but at cost to that end user.

Automated Originator Selection

Every text message has to originate from at least one of these types of numbers:

  • Short code
  • Virtual mobile number (VMN)
  • Text-enabled toll-free or landline number
  • Alphanumeric string

These are known as message originators and, when you send messages to different countries and mobile operators, you'll likely use more than one. Because it can be challenging to select the correct message originator for a given mobile number, our service can do this work for you. We call the capability Automated Originator Selection (AOS).

With AOS all you need to provide in the 'send message' request is the destination mobile phone number. Based on that we determine the country and then use the matching originator. If you use multiple originators for the same region, we may need more information in order to choose the correct originator for a particular end user.

For more information see Message originators.

Security and authentication

OpenMarket takes the security of your data very seriously. We work with a qualified independent security assessor to annually conduct third-party security audits across all our products. Our connections to mobile operators utilize industry-standard encryption technologies appropriate to the sensitivity of the information being transmitted. This means we use either VPN tunnels or SSL (TLS v1.1 or greater) to encrypt data being sent over public networks or private networks if required.

When you connect to us via our messaging APIs, you can utilize these security features: 

  • Using an HTTPS connection over secure port 443
  • Providing us with a whitelist of IP addresses from which we will accept API requests
  • Providing you with the OpenMarket IP addresses from which you should accept MO messages, delivery receipts and other notifications

For more about authenticating with OpenMarket, see Authenticating with OpenMarket.

High availability

OpenMarket offers a "4 nines" SLA to ensure that our global SMS messaging services are highly available. We operate multiple data centers in different geographic locations, each one providing multiple hosts for connections and supporting 100% of the traffic load. In our geo-redundant architecture, we provide one global endpoint for our SMS services; traffic is routed to the closest available data center. As such, traffic may tend to stay in one geographical region but it is not guaranteed.

Alternatively, you can load-balance your MT message traffic by connecting to multiple virtual hosts; however, if a virtual host becomes unavailable, you'll need to redirect traffic to a different, available host.

For MMS messaging, you also have the option of using a geo-redundant endpoint or connecting directly to the data centers.

For more details see High availability.

Support for single and multipart messages

A message that requires only one SMS is called a single-part message. The maximum size of a single-part message may differ amongst mobile operators in different regions. In the UK and the US, a single-part message can be up to 160 characters (assuming the GSM character set) or 70 characters (using the UCS-2 character set).

Any message that exceeds the byte size limitation is called a multipart message. (Other terms include "long" and "concatenated" messages.) These messages may require more than one SMS. To work around the limitation, mobile operators and handsets are able to combine multiple messages to form a single message experience for your end users. For example, if you send a GSM message of 500 characters to an end user in the UK, the message will be split into four parts and reconstructed as a long message on the end user's mobile handset.

Support for multipart messages is dependent on the region and mobile operator. Most operators support multipart messages of at least four parts. Some US operators support up to 20 parts. When you send an MT message request to us, we check whether the destination mobile operator accepts the message length. If not then we reject the message and send you an error response.

For more details see Single and multipart messages.


OpenMarket provides reporting capabilities that enable you to keep track of important data, such as the number of outgoing messages (MT messages) you send and the number of MTs that succeed or fail. Our web-based Dashboards & Reporting application uses a global data source and provides standard reports, custom report-building tools, and data visualization tools for creating graphical reporting dashboards.

For more details see SMS Dashboards & Reporting.

GDPR compliance

As of May 25, 2018, OpenMarket is compliant with the General Data Protection Regulation (GDPR). In terms of information security and data privacy regulations, including the GDPR, OpenMarket is considered a data processor while our customers are considered the data controller. When you use our messaging APIs and end users’ data travels through our network, we process that data on your behalf.

OpenMarket has its own Information Security team, and we utilize experts in the field of information privacy and regulatory compliance to develop our security review processes, build our security infrastructure, and implement our security policies. We work continuously to help you, as the data controller, meet your compliance requirements.

For additional information about how OpenMarket meets the GDPR, see our April 2018 white paper here.