SMS API & SaaS Integration: Essential FAQs Explained


6 min reading time

SMS API - A phone with a text message in a cloud surrounded by question marks

A quick recap from CALLR's Co-founders of our 7 most frequently asked questions on SMS API and SaaS integration

SMS APIs have a lot to offer SaaS platforms. However, for marketers, salespeople or even CEOs, it’s not always easy to know when and how to integrate a new solution into your techstack.  What are the red flags, contingencies, things to know in advance…before you take the plunge?

To help you navigate these waters, Florent and Taoufik, our CTO and CEO, went through some of the FAQs that come up when SaaS-ters are considering integrating an SMS API into their platform:


Photo of Taoufik Zagdoud

CALLR’s CEO and Co-founder Taoufik Zagdoud has well over a decade of experience working in the telecommunication industry,  including for SFR, Afone and IC TELECOM.


Photo of Florent ChauveauFlorent Chauveau is CALLR’s CTO and Co-founder, and a Full Stack Engineer with 9+ years of experience: Hardware, Network, Security, Data Modelling, Software Components, API, User Interface, UserExperience. 


How long does it usually take to integrate an SMS API?

Florent: This will depend entirely on how complex the workflow is that you want to put in place.  Do you have simple examples, where you just want to trigger an SMS when you get a new sign up? Or do you want to build a complex scenario where customers are sent a personalized SMS when they haven’t paid a monthly bill, in which case you’ll need to fetch information from your billing system, personalize the text with variables from your CRM, then pass through your CPaaS provider to send the message.  Using simple scenarios and assuming you can use an SDK, you could be done in a few hours, versus more complicated workflows that can take 6 months of development.

What if you’re a small SaaS start up, and you don’t have the resources internally to do a complex integration?

Florent: The easiest option is probably to use freelance developers that can come in, take a look at your documentation, SDK and get the job done for you.

What are frequent problems that come up during integration, and how can you avoid them?

Florent: If your developers don’t use the coding language of the SDK you’re interested in, this can be a problem (luckily, we offer our SDK in many frequently used languages). Your developers might also run into trouble if your workflow is too complex, or if your IT system isn’t compatible with your workflow.

SMS API - CALLR SDK languages

CALLR’s SDKs are available in the most frequently used coding languages

You also need to keep in mind how many requests you will want to make to the CPaaS API, and how long this will take.  For example, if you want to use the API to send 5,000 text messages using data from your CRM and billing system, and your IT system can’t process this, you could overload your servers and you won’t see on your DLR report that your messages have been sent or delivered.

To avoid bugs, check with your CTO about capacity planning and sizing, and decide on the kind of workflow you want with your tech team to make sure your IT system can handle this new activity.

Who is responsible for securing the data that goes through these SMS – the SaaS provider or SMS API provider?

Taoufik: The data is housed with the SaaS provider, and it stays there! The SMS API provider doesn’t and shouldn’t analyze or treat that data. At least at CALLR, we certainly don’t sell that data to databases, which is a very bad idea.  Depending on your sector of activity, there can be very strict laws regarding information privacy, like HIPPA in the United States. Do your due diligence.

How can you tell if your SaaS customers would benefit from SMS integration?

Several transactional notification examplesTaoufik: SaaS providers see the most value from SMS integration, (if they don’t already have a mobile app), with transactional notifications.  What you want from a transactional alert is that it gets read asap. SMS have the advantage of being instantaneously delivered and cross-device – they work everywhere in the world regardless of internet availability, what kind of telephone you have or whether it’s ‘smart’ or not.

SMS are also very effective for optimizing customer relationships – notifying people of an appointment by text instead of phone call can help companies avoid needless traffic that clogs phone lines and takes up resources.  If you’re a SaaS service that offers personal care or doctor appointment bookings, to give an example, SMS can be a very smart choice.

What kind of information should be sent by SMS vs Email, phone call, push notification?  In other words, when do you use what?

SMS API - A text messages from a driver to a riderTaoufik: It’s mostly about timing.  If you need something delivered in real time, use SMS or push notification over email.  If you think your user base may not have access to the internet (they’re travelling), or they haven’t installed your app or have opted out of push notifications, (as ComScore noted, at least in the U.S., “push fatigue” is on the rise), opt for SMS.  If you need a completely reliable way of getting in touch – let’s say, in an emergency – use voice. Voice is the most reassuring, most personal and most easy-to-use channel of communication.

Are some countries stricter than others when it comes to regulating A2P SMS?

Taoufik: Yes! In France, for example, marketing text messages are blocked any day of the week after 10 pm, all day Sunday and during public holidays. Other countries, such as the United States, United Arab Emirates, Russia or China are even more proactive: they require regulatory validation before any marketing campaign can be sent. Make sure you and your users are aware of the regulations in each country, and especially on the distinction between marketing and alerting.

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Key Takeaways

  • When building your desired SMS workflow, check with your CTO about capacity planning and sizing
  • The more complex the workflow, the longer the integration
  • SaaS providers are responsible for the data security of their users
  • SMS APIs are a particularly good choice for transactional notifications and improving customer relationship workflows, because of their immediacy and deliverability
  • Each country’s SMS regulations are different, so do your due diligence, especially regarding marketing vs alerting, times you can send, adult content, and opt-out options