What a DID number is, how much US and international DIDs cost, which countries need documents and which do not, and how to point a purchased number at your SIP trunk in a few minutes.
Short answer: a DID (Direct Inward Dialling) number is a phone number you rent from a carrier and point at your own SIP trunk or PBX. US DIDs are among the cheapest and fastest to activate; European and Asian numbers vary widely in price and in whether the regulator requires identity or address documents. Setup is a single SIP destination field once the number is provisioned.
A DID is an inbound number. Someone dials it on the PSTN, the carrier holding that range routes the call to your provider, and your provider hands it to you over SIP. From your side it arrives as an ordinary INVITE at your PBX, softphone, or contact-centre platform.
Three things define a DID commercially:
Capabilities matter as much as price: does it carry voice only, or voice plus SMS? How many concurrent inbound channels does it accept? A number that only supports two simultaneous calls is useless for a support line.
US DIDs are the easiest starting point. The NANP has deep number availability, wide area-code choice, and no identity requirement on most geographic ranges.
A practical warning: many platforms — WhatsApp, Telegram, banks, marketplaces — score numbers by type and will reject VoIP-classified DIDs for verification. If your use case is verification rather than telephony, read non-VoIP vs VoIP numbers before you spend money; a DID may simply be the wrong product.
Outside the NANP, three things change.
Price spread. Western European geographic numbers are usually modest monthly rentals. Some countries are structurally expensive — national ranges, mobile-format numbers, and markets with limited wholesale supply can run into hundreds of dollars a month. Turkey is a good example: an Istanbul or national 0850 number costs an order of magnitude more than a US local number because of how the market is supplied. We break the specifics down in the Turkish virtual number guide.
Documentation. This is the real dividing line, and it is regulatory, not a provider policy:
| Requirement | Typical countries | What is asked |
|---|---|---|
| No documents | USA, Canada, and several open markets | Email registration only |
| Local address proof | Much of Western Europe, incl. geographic German ranges | Address in the number's area |
| Full identity/company KYC | Regulated national ranges, some Asian and Middle Eastern markets | ID plus company registration |
No provider can sell you a document-free number in a market where the regulator forbids it. Anyone claiming otherwise is either reselling a number registered to someone else, or about to disconnect you. The German DID guide walks through exactly which German ranges need what.
Activation time. Document-free ranges activate in minutes. Regulated ranges wait on the local carrier — usually days.
Once the number is provisioned, routing it is trivial:
user@your-pbx.example.com.If you run FreePBX, the inbound-route step is covered in the FreePBX SIP trunk setup guide.
Two configuration details that cause most first-day tickets: make sure your firewall accepts SIP and RTP from the provider's signalling IPs, and check that your concurrent-channel limit is high enough for the inbound volume you expect.
How much does a US DID number cost? Local US numbers are the cheapest tier available and activate immediately. Toll-free numbers carry a similar rental but bill per inbound minute. Current pricing per country is on the DID numbers page.
Can I buy a DID number anonymously? In countries with no regulatory documentation requirement, yes — email signup and a crypto top-up are enough. In regulated markets, no, and that limit comes from the regulator. See buying DIDs and SIP trunks with crypto.
Can I receive SMS on a DID? Only on numbers explicitly flagged SMS-capable, and many online services still reject VoIP numbers for verification. For one-off verification codes, a dedicated OTP service is usually the better fit.
How many calls can a DID handle at once? As many as your channel limit allows. Set it to your expected peak plus headroom; inbound calls beyond the limit get a busy signal.
How fast is activation? Minutes for document-free ranges. Days for ranges where a local carrier must register an address.
Can I use one DID with multiple SIP trunks? A DID routes to one destination at a time, but that destination can be a PBX that distributes calls to as many extensions or agents as you like.
Browse availability and pricing by country on the DID numbers page, or pair a number with a crypto-funded SIP trunk so inbound and outbound run on the same balance.
Create an account to browse the full A-Z deck in your portal — Premium CLI and Standard clearly labelled, searchable by prefix or destination.