If your question isn't answered below, come to #dtmf on Freenode (or use Freenode's webchat). Please stick around for a while after asking your question, as we are a small team and are not awake 24/7!
Which browsers does voice support for French and German numbers work with?
Setting up forwarding works in any browser. For making and receiving calls within the browser, you need a browser with good WebRTC support, meaning at least Chrome 56, Firefox 51 or Edge 38.
Have the numbers been used before?
Our standard numbers come from a pool of numbers from each country, with new numbers regularly being added to the pool and older numbers released back to our suppliers. This means that your number may have been used by other parties recently, but will not have been in use for very long overall. If this is not acceptable for your needs, we offer pristine numbers at an additional cost. These numbers have never been used before.
Can I keep the number permanently?
Yes, we don't have a maximum rental period. As long as you keep your account balance above zero, the numbers you have rented will remain yours.
What happens if my account balance hits zero?
If your balance hits zero, all your rented numbers will be returned to the pool. We recommend that you keep your balance topped up if you want to keep your numbers.
Can I get a reminder if my balance gets low?
At present, no. We don't collect any information from our customers, not even an email address, so we don't have a way of sending this notification. You could use our API to check your balance automatically on a schedule, or simply forecast when you need to top up based on your rental cost per minute and your current balance. If there is enough demand for a notification we will come up with a better solution.
Do you have an API?
Yes - check out our API documentation.
Is DTMF available as a Tor hidden service?
It is, at iq4exwd2bn3akjgn.onion.
What technologies were used to build DTMF?
Glad you asked! The whole system is written in Rust, with Hyper for HTTP. We use Varnish in front as a proxy, and Hitch for TLS. It all runs on Arch Linux. We are slowly releasing parts of our Rust codebase as open-source software, beginning with the bitcoin-consensus Rust crate.