
Build a burner phone with Twilio and Kotlin - harel
https://www.twilio.com/blog/2017/07/building-a-fully-featured-burner-phone-with-kotlin.html
======
kchr
You might want to use the term "single-purpose number" or something similar.
Burner phone is colloquially used as a term for non-registered/anonymous
phones, which this isn't. Sure it sounds cool but people might assume that's
what they are buying...

~~~
wheelerwj
i was going to call you out for being overly precise, but given that this is
literally hosted by essentially a Telecom company its a pretty valid point.

That being said, burner doesn't mean anonymous. Burner means disposable.
Obviously you're not going to dispose of your account, application, and server
every time you're done with the number.

It's also not even a phone. I guess its a phone application in the most
minimal sense of the word..

~~~
cottsak
So here's by detailed response [https://www.twilio.com/blog/2017/07/building-
a-fully-feature...](https://www.twilio.com/blog/2017/07/building-a-fully-
featured-burner-phone-with-kotlin.html#comment-3423920873)

But I agree with kchr in principle. "Burner" may not _mean_ anonymous but it's
more often than not associated with anonymous and anonymity. It's the go-to
perception or association if you will.

So I think kchr and I are saying the same thing: the article is using the
burner/anonymity context as a little click-bait IMO and it's not a big deal
but it's a valid point.

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WisNorCan
The challenge for Twilio is that phone #s are a fixed quantity. The same #s
have been circulating across lots of different companies including being used
by spammers and in marketing campaigns and published across the Internet. Make
sure to search the Internet for any phone # you acquire from Twilio before
buying it. It may already have substantial call spam/undesirable organic
traffic associated with it.

On the flip side, there are already companies out there specializing in
monetizing misdials. They specifically look for phone #s that have been
retired recently with a lot of volume and then take those calls and resell as
leads for cars, insurance, etc.

~~~
gregorymichael
Greg from Twilio here.

Agreed on the challenge of working with a fixed number of phone numbers (and I
say this as someone who recently moved to NYC and would _love_ to own a 212
number).

In the industry, phone numbers that have a high-volume of unwanted traffic are
called "dirty numbers." Think of a number used by someone who signed up for
every sweepstakes they came across for 40 years, or maybe a number that's
particularly cute (you probably don't want to have a cellphone tied to
XXX-867-5309).

If we sold them, dirty numbers would be worse-than-useless for (almost all) of
our customers. So, whenever a phone number is released by a Twilio customer,
we reserve it for a minimum of two months before it can be purchased by
another account. We also monitor each reserved number until it reaches an
acceptably low number of phone calls.

If you do find yourself getting unwanted calls, you can use the <Reject>TwiML
verb[^1] to create a blacklist - your account won’t receive or be charged for
those calls.

[1]:
[https://www.twilio.com/docs/api/twiml/reject](https://www.twilio.com/docs/api/twiml/reject)

~~~
Sir_Substance
Hey Greg, uneducated but interested inquirer here: Once you're inside a phone
network, phone numbers can be as long as you like, can't they?

Could Twilio not arrange for a new "country code" to be assigned, possibly to
an industry working group of some kind, and then make the numbers ~64 digits
long? Then there should be more than enough to go around and to discard dirty
numbers, and the numbers could always be made larger in the future if needed?

~~~
walrus01
No, because 98% of peoples' phone systems out there expect a destination
number in a specific format. You can't just have a NANPA area phone number
that is arbitrarily long or has extra digits in it.

[https://en.wikipedia.org/wiki/North_American_Numbering_Plan](https://en.wikipedia.org/wiki/North_American_Numbering_Plan)

If you are way, way bigger than Twilio you can create a country code. Country
codes exist for special purposes like the Iridium satellite phone network. But
you cannot just create a country code for arbitrary purposes and expect it to
work with the world's PSTN/SS7 infrastructure, any more than you can choose an
arbitrary non-RC1918 /8 of IP space and start using it on the public Internet.

~~~
deftnerd
Maybe Twillio isn't big enough by themselves, but if you add in Google Voice,
Plivo, all the internet VoIP providers, and all the Cable Company VoIP
services, you are big enough.

Is there a VoIP trade association they are all members of? If so, the trade
association would be big enough to push for a new country code for the special
purpose of software-based telephony just like Iridium has one for satellite-
based telephony.

If that fails, Iridium is struggling. That hypothetical trade association
could acquire the country code from Iridium with special agreements to ensure
that Iridium still can lease numbers for no-cost for satellite-phone purposes.

~~~
walrus01
You're wrong that Iridium is "struggling", they're in the process of launching
and commissioning their next generation satellite system. It is used so
extensively by the US DoD, NATO militaries, aircraft based phone systems and
maritime systems that it's quite well positioned. It is the only real LEO
truly global coverage satellite phone network that includes high latitude
polar regions. The globalstar bent-pipe network architecture and coverage is a
joke.

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TACIXAT
Recently tried to use Twilio as a burner for registrations (project to set up
unique personas online). All modern websites that require a phone number are
also using a CNAM lookup and discriminate against VOIP numbers. I won't be
ditching my prepaid phone any time soon in exchange VOIP services.

~~~
bdcravens
Twilio even has a web UI for this lookup:
[https://www.twilio.com/lookup](https://www.twilio.com/lookup)

~~~
exhilaration
That's really cool, I'm plugging in my cell phone number and it's returning my
name and carrier. I didn't know services like these were available.

~~~
Sleeep
A lot of cellphone companies have this information displayed as an option for
numbers not saved in your contacts. My provider (Verizon) gave me this option
for a month for free when I first signed up then sent me a text that it was
additional cost if I wanted to keep it. Then they started displaying that
information for business lines for free. Later when I got my new phone it
stopped for some reason.

------
packetized
I think that the disconnect here is that this isn't a "burner phone" the way
many people think of them, but rather some sort of call/SMS firewall.

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Endy
At the risk of sounding silly, what advantage does this provide over buying a
$20 TracFone for cash and activating it without an account on TracFone.com
over a public Wi-Fi?

Or, better yet, not bothering to "activate" it, but using it only over Wi-Fi,
creating a new Google account, and downloading Talkatone (or the Hangouts
Messenger to create a Google Voice account connected to your new account)?

~~~
gregorymichael
Greg from Twilio here.

Not a silly question at all. Developers certainly have a propensity to
recreate the wheel for the sake of recreating the wheel -- though I think that
many of us would agree that the act of creating is itself the advantage.

That said, a few things:

1\. Costs less. A Twilio phone number is $1 per month (in the US). A minute of
calling costs $0.01.

2\. You can get a new number any time you want.

3\. You get to write code.

Don't want to speak for Marcos (though he happens to be sitting 10 feet from
me at the moment), but my guess is that what excites him most about writing
this post isn't that other developers will copy it line for line. It's that
they'll use it as a jumping off point -- that it inspires and equips
developers to ship their own inventions.

For an example of this, check out the folks at Burner app who used the similar
concept (pre-Kotlin) to build an entire business around this idea.

[1]: [https://www.twilio.com/blog/2012/08/burner-app-offers-
alias-...](https://www.twilio.com/blog/2012/08/burner-app-offers-alias-phone-
numbers-powered-by-twilio.html)

~~~
CodeWriter23
For example, this is the same model Uber uses to anonymize the driver's and
rider's phone numbers. Probably when a driver signs off their number is
released for a new driver to use until they sign off.

~~~
rahimnathwani
Do they use a unique number per driver per shift? If you know the rider's and
driver's phone numbers, then you can connect them anonymously with just a
single phone number. When I call that number, see if I have a ride in
progress, and put me through to the right driver.

This assumes no pooling. With pooling you might need 4 numbers, as the driver
could have up to 4 separate passengers they want to contact.

------
blago
I've been doing this for a long time and there is one big, real-world, gotcha
- most business (such as Uber, Lyft, Microsoft) can't send text messages to
Twilio numbers. I filed a ticket with their customer support a few years ago
and they basically swept it under the rug.

~~~
blago
BTW, nor can you use your Twilio number to send a text message to a short code
provided by Twilio to a third party such as Uber:
[https://www.twilio.com/help/faq/sms/can-my-twilio-number-
sen...](https://www.twilio.com/help/faq/sms/can-my-twilio-number-send-sms-to-
a-non-twilio-short-code)

------
thedangler
Or download a real burner phone app that lets you buy numbers and associate
them for different things. There are plenty on the app store for iOS and
Android.

Still looks like a fun project.

~~~
pmiller2
That defeats the purpose of a burner phone by not being anonymous.

~~~
Sleeep
Neither is this. I don't know much about Twilio but when I clicked on the link
in the article it asked for a bunch of personal information.

I also don't know how this is any different from, say, Google Voice?

------
vedanta
Is it just me or wouldn't everyone just rather live in a world where privacy
is respected by third parties just like a first party would. The do not call
law has developed too many exceptions or needs strengthening methinks. If I'm
getting a spam call on a burner number vs. my normal number, have I really
saved any time? or privacy or security if the number can be reused in
malicious ways?

I save numbers for 2nd factor auth, and I seem to get yahoo/msft messages from
the same numbers, also github sometimes. Number reuse is definitely a problem.
A PKI cert system for numbers/calls would be great to have in this case. I
want to know for sure that I'm getting my 2nd factor auth code from msft,
regardless of the number they're using.

------
ozfive
Then you'll pay for all the phone calls from marketers. Thanks but no thanks

~~~
gregorymichael
Greg from Twilio here.

Totally understand the concern there, especially since you're already paying
for your cellphone.

I did something similar a couple years ago when we were shopping for a car. A
lot of car shopping sites are basically lead generators for dealerships and
you need to provide a number to get real info. I used a Twilio number
forwarded to my cellphone.

The deluge of calls started immediately. After 48 hours, when we had all the
information we needed, I released the Twilio number and incurred no further
charges.

Total cost was $1 (per month) for the phone number and $0.01 per minute for
the inbound calls. Upside was that my phone stopped ringing the moment I was
done talking to salesmen.

~~~
ozfive
So what you're saying is this tutorial was written by a twilio sales/marketing
employee?

~~~
gknoy
It's on the Twilio.com blog, so I think that it is pretty reasonable to assume
that it's written by a Twilio employee. :-)

~~~
ozfive
I'm still waking up... :/

~~~
kchr
Stick it to the Man!

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cupcakestand
Nice idea, confusing title (burner phone??).

~~~
Sleeep
"Burner phone" is a colloquium used in the United States referring to limited
use prepaid phone, separate from your main phone, that's not tied to your
identity. Usually used for drug deals or other criminal behavior.

This isn't really a burner phone as the Twilio link I clicked asked me for a
bunch of personal information first.

~~~
Sleeep
I meant to write colloquialism not colloquium. Burned (heh) by auto correct.

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mkez00
Author is building a Spring MVC application but labels it as a "Kotlin app".
Is it because Kotlin is the new hotness and the Spring Framework is "old" and
"uncool"?

~~~
orclev
I imagine it has more to do with the fact that simply saying "Spring app" will
make most people assume it's written in Java. It would perhaps be better to
say it's a Kotlin Spring app, but honestly the web framework being used is
probably less important than the language it's being written in.

------
Jamieee
I've been using ring4 for throw away numbers and it's been decent. Plus there
are often lots of promo codes to use.

Code for 20 extra credits if you check it out: INV-DKCSGJHX

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Animats
Er, you realize Twilo logs everything, right? You can log into Twilio and read
your own logs.

~~~
gregorymichael
Greg from Twilio here.

Privacy is _incredibly_ important to us. You can delete the logs of any call
or message that you don't want residing on our servers.

[https://www.twilio.com/blog/2014/11/introducing-delete-
api-n...](https://www.twilio.com/blog/2014/11/introducing-delete-api-nt.html)

~~~
deftnerd
According to that blog entry, it just makes that data hidden on the front-end
and from the API, but it still resides on your servers. Has that policy
changed?

Soft-deletes, which the blog indicates that you are doing, is very different
from actual deletion.

To make the distinction clear, if a log of a call or message is deleted, can
it be given to law enforcement? If so, it's not truly deleted.

------
SeanDav
Is this a USA solution only, or also applicable in UK, EU, Rest of World?

~~~
Nexxxeh
UK for sure, dunno about RoW number availability. When you pick a number
though, do check that the number supports voice and SMS. Not all do.

------
burntrelish1273
bur.nr is available for $679.99 :D

