[chrisdevereux]

It should be possible for IFTTT to send an SMS with the user's number as sender without involving the phone at all. Which might be preferable anyway, as it doesn't rely on your phone being reachable when an event is triggered.

Not sure how much it would cost per message and whether it's feasible for a free service like IFTT, but it can be done.

[toomuchtodo]

You are unable to spoof SMS numbers. Twilio has documentation on this if you'd like more info (experience: I tried, so I could SMS birthday messages to my contacts without remembering, but having it look like it came from me).

[adrianpike]

You're absolutely able to spoof SMS numbers from a technical standpoint, but you'll have to go straight to an SMSC or aggregator that lets you do it.

I haven't checked in years, but we had to write an SMPP library to pull it off. That sucked.

[toomuchtodo]

I should have qualified my statement.

[willtheperson]

Is that really possible? I've wanted to do that before and looked into Twilio but it's basically number spoofing and would make spamming people far too easy.

If you've found a way, I'd love to hear it

[chrisdevereux]

There are services that can do this (Skype, for example) but on closer inspection, looks like it's not allowed in some territories (including the US).

https://support.skype.com/en/faq/FA672/how-do-i-show-my-mobi...

http://en.wikipedia.org/wiki/SMS_spoofing

[biot]

Twilio lets you deliver SMS from a number other than your Twilio number. The one caveat is that you need to have Twilio verify the external number first, two-factor auth style.

EDIT: Oops, apparently this is only for voice calling: http://www.twilio.com/help/faq/phone-numbers/whats-the-diffe...