📆 November 21, 2020 | ⏱️ 7 minutes read | 🏷️ computing

Get an Anonymous Phone Number with DTMF.io


DTMF.io has shut down. Links to the website have been replaced with archival links.


I am not in any way affiliated with DTMF.io. I was not paid to write this (I wish). If I am paid to write about something, I will always disclose it. I will never write things I do not agree with for money. I just happen to think DTMF.io is a good service and people ought to know about it.


One reason I feel compelled to write about privacy and anonymity is there are so many poorly researched guides out there that don’t offer real anonymity, but advertise that they do. Existing guides either have a freedom issue, privacy issue, or other issue which makes them less than ideal. DTMF.io really impressed me, so I decided to share it with all of you. Also, I plan on writing a guide on anonymous e-commerce in the future. When I do that, this post will make a good reference since a phone number is required in many cases when doing e-commerce.

Sometimes I get asked why I insist on such high standards of anonymity, privacy and freedom in everything. What on earth kind of threat model do I have to insist on such high standards? No, I don’t possess state secrets or anything of that level. If I did, I wouldn’t be blogging about Big Brother since Big Brother is probably on the list of keywords that gets flagged by 3 letter agencies. My philosophy on this actually aligns pretty closely with Richard Stallman. I’m just very ethically motivated. Specifically, it’s a matter of preserving my freedom and resisting Big Brother. It’s not just that I want to resist Big Brother. I think everyone ought to hold high standards like I do in order to raise the bar on privacy and protect democracy.

Problems with Existing Anonymous Phone Number Guides

I’ll begin by pointing out a few problems with existing guides out there for obtaining an anonymous phone number. Let’s take a look at appsverse as a case study. Their first method for getting an untraceable phone number is a burner phone.

Why Not Use Burner Phones?

There are 3 major problems that come to mind with burner phones:

  1. They are materially wasteful. All the effort that went into manufacturing the burner phone and it’s just going to be used temporarily, perhaps just once, then become e-waste. They’re bad for the environment.
  2. They run proprietary operating systems and software. This is bad for your freedom. Because of their freedom issues, there’s no way to ensure they don’t covertly surveil you. The whole point is that they’re supposed to be anonymous, so this is kind of self-defeating.
  3. You’ll need to remove the batteries or put the phone in a Faraday bag when you aren’t using it. Turning it off isn’t effective since you might accidentally hit the power button. Since we’re trying to preserve the number’s anonymity against Big Brother, it can’t ping nearby cell towers at places you’re associated with. You can’t send or receive sms or calls unless you take it out of the bag, so you’ll have to only use it at a remote location. Going to a remote location just to make a call or check your messages is very inconvenient.

Just Hide My Caller ID?

The second method appsverse suggests is hiding your caller ID. This isn’t anonymous against Big Brother so we can disregard it.

What About Apps?

Method 3 is phone apps. Appsverse recommends phoner, which is a proprietary app that give you burner phone numbers. The problem is most of these apps are proprietary and you should never install them. Don’t go through the Goo-lag Play Store or crApple App Store looking for burner phone number apps. Almost all of them are proprietary garbage. Another example is Burnerapp.com. It’s proprietary and requires your name, email and phone number tied to your real identity. Also, there’s no way to pay anonymously. How can your phone number be truly anonymous if you have to identify yourself to get it?

SMS Privacy

Update (19 Sept. 2022): This service no longer exists.

SMSPrivacy.org is worth a mention. You can send and receive sms messages over a web interface. The sign up process doesn’t require providing any personal information. It has a v2 onion address and doesn’t require JavaScript which is always a plus. The only gripe I have is the price. 0.0015 BTC per day per phone number is asking too much for most people. It’s even more expensive for a physical phone number that you can use to sign up for websites.

Introducing DTMF.io

DTMF.io is the best service I’ve come across for an anonymous phone number. Like SMS Privacy, it can be accessed over a web portal. There is no third party JavaScript. The web portal is available in several languages. It requires no personally identifiable information (PII) to sign up and supports 2-factor authentication. Unlike SMS Privacy, it has a more reasonable price tag. It has a v3 onion address for Tor. It supplies landline, mobile, SIM mobile and toll-free phone numbers from all over the world. You can pay with Bitcoin, Lightning, Ethereum, Litecoin, Monero and Perfect Money. Monero support is a huge plus since it’s the only cryptocurrency with private payments by default. You can also make calls using SIP or your web browser. SIP is convenient because it allows you to bypass the JavaScript trap of using the web portal. Like SMS Privacy, it does not require you to enable JavaScript in the browser for sign up or sms, although calling won’t work without it. DTMF.io has an API available to pro and business customers allowing automated account control, sms and calling. Their terms of service and privacy policy seem reasonable enough. You can’t expect much privacy using sms anyway, which is why I can’t recommend using it for very much except maybe website sign up and only if it’s required. I also recommend you avoid sharing PII using your anonymous number. Keep in mind a social graph could still be constructed of which numbers you’re contacting and at what time. To reduce linkability, you should use a different number for each website you sign up for, if you can afford it.

I know I criticized using apps for an anonymous number before, but that’s because they are proprietary. DTMF.io supports SIP. So, you can use free (as in freedom) SIP calling apps to make calls or you can use the official free (as in freedom) DTMF.io app for sms and calling currently available on Android. You can build it from source for Android, iOS, Windows, Mac and GNU/Linux. Voice calls aren’t currently supported in Windows or GNU/Linux though. It does not require Goolag Play Services and only asks for permissions it needs. It will even work without camera, microphone or contacts permissions enabled.

The only recommendation I’d make if you plan on using it is that you pay anonymously and don’t provide an identifying email address on sign up. Also, if you use the Android app, you should proxy the connection over a VPN or Tor (with Orbot) that way the service never gets your real IP address. Use Tor Browser with the onion address to access it over the web. Other than that I don’t know what more you can ask for. The other anonymous phone number services (except for SMS Privacy) either don’t allow you to pay anonymously, require identifying information, have proprietary JavaScript, or some other problem that makes them unsuitable. As far as I can tell, DTMF.io is the only game in town for a cheap, ethical, anonymous phone number. If you’re using anything else, you should definitely make the switch.