Use any VoIP solution
Already have a VoIP provider, a PBX or an AI voice platform? Send your FlyNumber's calls straight to it.
Incoming calls sent to a VoIP address have no per-minute charges: unlimited incoming minutes*.
Set the number's Call Handling to Forward to SIP / VoIP Address and enter your provider's SIP host, an optional port and username, and UDP or TLS as the transport. Here's how to set your FlyNumber to VoIP.
Prefer not to run your own VoIP? Choose FlyNumber SIP instead. We give you SIP credentials for any softphone, desk phone or PBX, help you set it up, and you make and receive calls with just the number.
Integrate with any 3rd party provider or system
- We send calls to major VoIP providers and platforms like Flowroute, Twilio, Callcentric, Telnyx, OnSIP and 3CX.
- On-premise systems work too: Asterisk, FreePBX, FreeSWITCH or any other SIP server you run yourself.
- FlyNumber works with any VoIP solution that accepts incoming SIP calls (SIP is the standard that VoIP apps, desk phones and PBXs use). All we need is your provider's SIP host, an optional port and username, and whether to use UDP or TLS.
- If your server filters by IP address, allow FlyNumber's server first. The address is in the docs.
- Rather have the calls on a regular phone? That's call forwarding, billed per minute at the rates page prices.
Popular VoIP providers we send calls to
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Looking for a specific provider? Browse all the VoIP providers we work with.
AI Voice Platforms
Connect your FlyNumber to AI voice agent platforms like VAPI, ElevenLabs, LiveKit, Retell and Bland AI for automated call handling.
These platforms let you build AI-powered assistants that answer calls, schedule appointments and handle customer inquiries around the clock.
With VAPI for example, you point your FlyNumber to a SIP address like +{your_number}@{credential_id}.sip.vapi.ai with no SIP registration required. Some platforms need TLS rather than UDP; just set the transport to match.
Check out our VAPI setup guide for step-by-step instructions. If your platform expects a registered SIP connection, use FlyNumber SIP instead.
FlyNumber SIP or the optional cloud phone system?
Forwarding to your own VoIP covers incoming calls. Want to call out with your FlyNumber as the caller ID too? Switch the number to FlyNumber SIP any time from your panel.
FlyNumber SIP gives you SIP credentials for incoming and outgoing calls, no phone system needed. Register up to 5 devices and ring them all at once or one after another, with voicemail built in and TLS encryption available.
Incoming calls are included with the number's monthly rate. Outgoing calls are billed per minute from your prepaid balance at the rates page prices, with no setup fee and no monthly fee for FlyNumber SIP itself.
The cloud phone system is the optional add-on for call routing: voice menus, ring groups, queues, business hours, a blocklist and call recording, for $14.95/month flat across your whole account. Usually you don't need it: see when it's worth adding.
Four ways to use your FlyNumber
Note
Switch between them any time in your panel. A fifth option, Park the Number, stops the number ringing anywhere (callers hear busy) with no call charges.
3rd party PBX software we work with
Point your FlyNumber at your PBX's SIP address for incoming calls, or register the PBX to FlyNumber SIP to make calls out as well. The FlyNumber SIP docs cover FreePBX, Asterisk, FreeSWITCH and 3CX step by step.
is the go-to framework for building powerful communications applications, from IP PBX systems to VoIP gateways.
handles large-scale telephony applications easily, it's flexible and uses LUA scripting.
is very popular among businesses and easily integrates with SIP trunks and desktop VoIP phones.
handles high-performance SIP routing, making it ideal for large-scale VoIP and real-time communication deployments.
Frequently Asked Questions
What do I need to enter to send calls to my VoIP provider?
Set the number's Call Handling to Forward to SIP / VoIP Address and enter your provider's SIP host (a domain or IP address). Port and username are optional: leave the port blank unless your server uses a non-standard one, and add a username when your provider or PBX expects a specific account or extension. Pick UDP (the default) or TLS as the transport, then save. The change takes effect right away.
Are incoming calls to my VoIP address really unlimited?
Yes. When your FlyNumber sends calls to a SIP / VoIP address there are no per-minute charges on incoming calls, so you get unlimited incoming minutes*. The exception is toll-free and metered numbers, which carry a per-minute incoming rate no matter how calls are handled. You can check those on the rates page.
Can I make outgoing calls with my FlyNumber as the caller ID?
Yes, with FlyNumber SIP. Switch the number's Call Handling to FlyNumber SIP and register any softphone, desk phone or PBX with the credentials we give you. Incoming calls stay included with the number's monthly rate; outgoing calls are billed per minute from your prepaid balance at the prices on the rates page. Some number types restrict outbound calling due to local regulations.
My provider only accepts registered SIP connections. Can I still use it?
Yes. Forward to SIP / VoIP Address connects to your endpoint without registering, so if your provider or AI platform insists on a registered (authenticated) SIP connection, choose FlyNumber SIP instead. Your platform then registers to FlyNumber with the credentials we issue and receives the calls that way.
Is the connection to my VoIP server encrypted?
It can be. Choose TLS as the transport and the leg between FlyNumber and your server is encrypted (signaling over TLS, audio with SRTP). Your server needs to support SRTP for this to work. UDP is the default and works with most SIP servers and softphones.
Do I need the cloud phone system to use my own VoIP provider?
No. Forwarding to your VoIP address and FlyNumber SIP both work on their own. The cloud phone system is an optional add-on for call routing: voice menus, ring groups, queues, business hours and call recording, for $14.95/month flat across your whole account.
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Get your virtual phone number today
- A virtual phone number from $2.95/month in 90 countries. See pricing for the 3, 6 and 12-month discounts.
- Pick your own number in the US, Canada, Australia and 50+ other countries.
- Choose how calls are handled when you order, and change it any time from your panel.
- No contracts. Auto-Renew is on by default and every renewal is a one-time charge; turn it off any time to let a number lapse.
- Pay by card, PayPal or prepaid balance.
- Chat support, docs and a community forum.
