Twilio or Local SIP Numbers? Choosing the Right Telephony for Your AI Receptionist
Quick answer: Choose Twilio when you need numbers across many countries and want to manage your own telephony account. Choose a local carrier SIP route when the callers are in one market, such as India, and you want local numbers without setting up a separate account. The AI receptionist can sit on either, so the decision is about numbers, not about the AI.
Telephony is the part nobody mentions
Most AI receptionist comparisons focus on voices and features. Telephony gets less attention, yet it determines which phone number callers dial, where the call is routed and who manages the account. A strong voice model is of little use if the number does not suit your customers.
Telephony is the layer that connects the public phone network to the receptionist. There are two broad options.
Option 1: Twilio
Twilio is a cloud communications platform used by developers and agencies worldwide. For an AI receptionist, its main advantages are:
- Global numbers. Numbers in many countries, useful for agencies with clients in several markets.
- Bring your own account. Agencies that already use Twilio can connect their existing account and keep control of billing and numbers.
- A familiar tool. Many technical teams already know how to manage it.
The trade-off is that you manage a separate account and its costs, and number rules vary by country. Some countries require identity or address verification before a number is provisioned, so check requirements for each market you serve.
Option 2: Local carrier SIP
SIP is a standard method of carrying voice calls over the internet. A carrier SIP route connects the receptionist to the telephone network through a carrier, rather than through a communications platform.
For India, GMB Briefcase offers a carrier SIP route for Indian local numbers, and no separate account is required. The benefits are:
- Local numbers. Callers in India dial a number that looks and feels local, which matters for trust in neighbourhood businesses.
- Fewer moving parts. One platform handles the receptionist and the number.
- Simpler onboarding for small clients. No telephony account to create.
The trade-off is that a local route is built around one market. An agency serving many countries will probably need a second option.
Side-by-side comparison
Best for
Multi-country agencies and technical teams
Businesses with callers in India
Number coverage
Many countries
Indian local numbers
Account needed
Your own Twilio account, or the platform’s
None separate
Control over billing
High if you bring your own account
Handled through the platform
Setup effort
Moderate
Light
Local feel for callers
Depends on the country and number type
Strong in India
Questions to ask before you choose
- Where are the callers? Match the number type to the market. A Mumbai customer is more likely to answer a call back from, or trust a listing with, a local number.
- Do you need to keep the existing number? If so, call forwarding from the current number is usually simpler than porting.
- Who should own the number? Agencies that want to move clients between tools will prefer accounts they control.
- How many markets do you serve? One country points toward a local route. Several point toward a global provider.
- What are the verification requirements? Check the rules for each country before promising a go-live date.
- What is the fallback? Decide where calls go if the receptionist is unreachable, such as a forwarding number or voicemail.
The AI layer is separate
Whichever route you choose, the AI behind the receptionist is a separate decision. GMB Briefcase lets agencies bring their own API key or use platform defaults, and choose between models including OpenAI, Google Gemini, Sarvam for Indian vernacular languages and proprietary Marathi voice models. Mixing and matching is possible: a local number with a vernacular voice model, or a Twilio number with a default English model.
A simple rule of thumb
If all your clients and callers are in India, start with a local carrier route. If you serve several countries or already run Twilio, use Twilio. If you are mixed, use both and assign each client to the better fit.
FAQ
Do I need Twilio to run an AI receptionist? No. Twilio is one option. A carrier SIP route is another, for markets where it is offered.
Can I keep my existing business number? Usually yes. Forwarding calls to the receptionist number lets you keep the number customers already know.
Does the telephony choice change how the AI sounds? Not directly. The voice comes from the AI model. The telephony choice affects the number, routing and account management.
