Decision framework
Compare DID providers at the market and use-case level.
A global DID number gives callers an inbound telephone number that can route to a SIP endpoint, PBX, contact center or another approved destination. The word global does not mean every number type is available in every city or that every order follows the same documentation process.
A useful provider comparison starts with the exact market, number type, business identity, intended use and receiving call flow. It then checks inbound capacity, activation requirements, recurring terms, porting and support for future routing changes.
01 / Coverage
Check coverage at the city and number-type level.
A provider may support a country while not offering the city, rate center or number type your project needs. Ask for current availability against a structured list and note whether each item is new inventory, subject to review or available through porting.
Geographic scope
Specify country, city, area code or rate center plus the quantity required now and the expected expansion schedule.
Number category
Identify local, national, toll-free, mobile or other requested number types because features, charging and documentation can differ.
Feature scope
Confirm inbound voice, SMS if required, caller display, concurrent call capacity, number portability and any market-specific restrictions.
Practical check: Ask the provider to date the availability response because DID inventory and market rules can change between planning and ordering.
02 / Eligibility
Match business use to local documentation requirements.
Some markets require company registration, identification, address evidence, local presence or a clear service description. Requirements can depend on who will use the number, how it is presented and where calls are received.
Collect the documents before the desired activation date and confirm whose name will appear on the order. A reseller or service provider may need information about the end business as well as its own account.
Business identity
Prepare legal organization name, registration information, website, address, authorized contact and any end-customer details required for the market.
Intended use
Describe whether the number supports customer service, sales, support, an application or another lawful workflow and identify the caller-facing brand.
Address and local presence
Confirm whether the requested number needs a local address, proof of presence or a geographic relationship to the number area.
Practical check: Do not submit altered or mismatched documents; ask for the exact acceptable document list and validity requirements for the requested market.
03 / Routing
Plan SIP delivery, capacity and failover.
The number is only the customer-facing entry point. The receiving platform must accept the call, recognize the destination, support the agreed codec and handle the expected busy-hour demand.
Destination format
Confirm the SIP URI or IP destination, number format, inbound headers and how the receiving PBX or contact center maps each DID to a queue or extension.
Concurrent calls
Estimate normal and peak active inbound calls, queue behavior, call duration and the capacity or channel model applied to each number or account.
Resilience and testing
Document secondary routing, timeout behavior, codec and DTMF tests, caller experience and the process for changing a destination.
Practical check: Test the complete inbound flow from a real external network through the DID to the final queue or extension, including any overflow path.
04 / Lifecycle
Review activation, recurring charges, porting and cancellation.
DID costs can include setup, recurring rental, usage, channels, regulatory charges and porting. The operational terms are equally important because numbers can become part of customer-facing marketing and support workflows.
Activation and recurring terms
Confirm setup charges, monthly fees, included capacity, usage rates, minimum term, renewal and the expected activation sequence.
Porting and ownership
Ask whether inbound and outbound porting is supported, what documentation is needed, who controls the number and how service continuity is handled.
Changes and cancellation
Document routing-change lead times, support contacts, suspension conditions, cancellation notice and what happens to the number at termination.
Practical check: Keep an internal inventory that maps each DID to its market, business owner, documentation, SIP route, renewal and customer-facing use.
Ready-to-send brief
Global DID number request checklist
Include these details so availability, compliance and routing can be reviewed together.
- Legal organization name, website and authorized contact
- Country, city, area code or rate center for each request
- Local, national, toll-free, mobile or other number type
- Quantity required at launch and expected future volume
- Business use, caller-facing brand and end-customer relationship
- Available company, identity, address or local-presence documents
- SIP endpoint, PBX or contact center receiving the calls
- Expected normal and peak concurrent inbound calls
- Codec, DTMF, number-format and header requirements
- Primary and backup routing destinations
- Porting requirement and current provider details if applicable
- Target activation date and technical test contacts
Common questions
Global DID buying questions
What is the difference between a DID and a virtual number?
The terms are often used interchangeably for an inbound telephone number that routes calls to another voice destination. DID emphasizes direct inward dialing, while virtual number emphasizes that no separate physical line is required for the number.
Can I buy a DID number without local documents?
That depends on the country, number type and use case. Some markets require company, identity, address or local-presence documents. Check the exact requirements before treating availability as confirmed.
Can one DID receive multiple simultaneous calls?
It may be possible, but concurrent-call capacity depends on the provider, number product, account and receiving SIP platform. Confirm the capacity model and test expected busy-hour behavior.
Can a global DID number be ported later?
Portability varies by market, number type, provider and account status. Ask about inbound and outbound porting, ownership, documents, timing and continuity before ordering a number that will be widely published.