What is the deal with Twilio and International SMS?

Question

I've been working with Twilio to program SMS functionality on my app, and it seems that Twilio works best with US numbers and not so well with international numbers. I've done some research and have learned about an August 16th fiasco that resulted inthe SMS functionality being shut off by Twilio. Also through testing I have learned that some international carriers are not supported by Twilio. So some of my friends abroad aren't receiving my Twilio SMS messages.

Can anyone provide further insight into this issue? Is international SMS well supported by Twilio? If not, how many carriers and which ones ARE supported? Finally is there a better SMS service provider that can guarantee full support for all if not the more prevalent carriers internationally?

Thanks for the support everyone and any clarification on this issue.

Answer 1

Good questions all - this information can be kind of hard to find on our website right now. If I'm picking up what you're putting down correctly, you're curious what kind of availability Twilio SMS has internationally and what the deliverability is like.

The matrix on what kind of Twilio service is available where can get a little complicated (which we have here a little buried in our FAQ: http://www.twilio.com/help/faq/phone-numbers/which-countries-does-twilio-have-phone-numbers-in-and-what-are-their-capabilities), but for SMS it breaks down like this:

• Twilio phone numbers that can send and receive SMS are available in the US, Canada and the UK.
• US and Canadian numbers can send and receive to 190 countries to over 1,000 carriers. To see what the pricing for each country and carrier per message, check out this page: https://www.twilio.com/sms/pricing
• UK numbers can currently send and receive SMS reliably within the UK. As the numbers themselves are geographic, some international carriers do not allow messages to be sent or received to them. This might be a possible root cause for some of the deliverability issues you experienced.
• All other phone numbers we make available in other countries only have support for Twilio Voice - these numbers cannot send or receive SMS at all.

I'm not aware of any SMS related incident on 16 August, though we did have intermittent service interruption the week before on 9 August lasting a little under 90 minutes. For future reference, we communicate all our service issues on an independently hosted status board here: http://status.twilio.com/ Any issue, root cause and resolution are posted there for your review.

Finally, if you have a specific question about a number, deliverability to a particular carrier or handset, or would just like to share a cool hack, I definitely encourage you to engage one-on-one with our support crew at [email protected] or come meet one of my fellow developer evangelists when you're out at a programming event. We'd love to see what you're working on and if there is anything we can do to help.

Thanks Kev!

Rob - devangel at Twilio