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Bring your PBX to the cloud — the easy way.

SIP trunking providers aren’t the same. Nextiva’s business voice network is built for reliability. There's no new equipment needed.

SIP Trunking
Nextiva Supports every major PBX system:
video on what sip trunking is

What is a SIP trunk?

A SIP trunk provides voice connectivity to the telephone network by only using an internet connection. Based on the Session Initiation Protocol, SIP trunks handle a high volume of inbound or outbound calls using a Private Branch Exchange (PBX) server.

Why go with SIP trunking?

SIP Scalable voice icon

Scalable voice

Easily add trunks, channels, and DIDs as you grow.

SIP Cloud icon

Cloud redundancy

Eight U.S. data centers give you superior call reliability.

SIP Flexible pricing icon

Flexible pricing

SIP trunk pricing that saves you more on business voice.

Get more from your PBX with SIP trunking.

Carrier-grade PSTN connectivity. Easy setup. No code needed.

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Online management

Manage your credentials, direct-dial numbers, and more from a web-based admin portal. Goodbye, terminal.

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Fraud mitigation

We’ll let you know if we see unusual call activity. Thwart abuse and fraud in a few clicks.

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Enhanced 911 (E911)

Ensure users are safe with turnkey E911 functionality. Supports physical location for public safety operators.

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Automatic failover

If your PBX goes offline, no problem. Cloud connectivity lets you direct calls to another destination.

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Detailed call records

Need to research call detail records? Administrators can view CDRs securely and in minutes.

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Rapid setup

Ready-to-use SIP trunks mean you can deploy the same day without any coding.

Flexible SIP trunk pricing

Unlimited calling. Affordable trunking. Why not both?



Per month
plus $0.008 per minute

Get a quote

100 minutes included

Fast, free account setup

Eight U.S. points of presence

Award-winning 24/7 support



Per month
Unlimited calls nationwide

Get a quote All Metered features, plus:

No per-minute charges

Toll-free number included

Scale up as you need

Volume discounts available

Got pricing questions?

Chat with an expert
How it works

Start using SIP trunks in four steps.

Get a personalized quote.

Get a custom quote for SIP trunk pricing. Even if you’re just getting started, no problem. Your quote reflects all taxes and fees.

Check your compatibility.

Our SIP trunking solution works with dozens of popular IP PBX systems. We’ll confirm your hardware works with us.

Select or port numbers.

We’ll gather your needs, including extra phone numbers (DIDs) and toll-free numbers. You're supported at every step.

Establish PBX connectivity.

You’ll receive your credentials to manage your SIP service. From there, begin placing calls using our SIP trunking infrastructure.

How does SIP trunking compare to business VoIP?

Not sure about whether SIP trunking is right for
you? Here’s a simple comparison.


SIP Trunking

Business VoIP


Network/IT experience

No tech experience needed


$14.95 - $24.95 per line1

$22.95/month per user2



Direct-dial numbers (DIDs)



Nationwide calling



International long distance



Call logs



Public Switched Telephone Network
(PSTN) connectivity



On-premises hardware

Yes (PBX)


Mobile apps


Business voicemail


Voicemail transcription


Call recording


Auto attendants


Text messaging (SMS)


Call queues


Conference calls


Video conferencing


1 Metered SIP trunking pricing varies, see pricing table.

2 Nextiva Essential plan for 100 users with an annual agreement.

3 Add-on feature or bundled with available plans.

Nextiva is the last SIP trunk provider you’ll ever need.

IT professionals choose Nextiva over other SIP trunking
providers for these reasons:

Guided support

Changing voice providers is a big deal. We work with you to ensure porting is successful.

Reliability & uptime

We connected over 1 billion calls last year. We've built the most reliable VoIP network in the industry.

Superb call quality

Redundant SIP servers give you
low-latency voice connectivity with multiple call routes.

Hassle-free setup

Standards-compliant credentials mean you just copy them into your PBX and you’re done.

SIP Trunking FAQs

You can expect to pay between $15-25 per month for each line depending on the calling plan.

SIP trunks are sold in metered (pay-as-you-go) or unlimited plans. Some SIP trunk providers charge extra for account setup, support, and porting, but Nextiva includes these for free.

If you have a high call volume like a call center, you could save a lot with the unlimited plan. However, if you just need phone service connectivity with light use, then the metered SIP trunking solution is for you.

Head over to our blog for more information on SIP trunk costs.

SIP is short for Session Initiation Protocol. It’s a universal standard for managing real-time multimedia between users. It can be used for real-time audio, video conferencing, and instant messages.

Voice over Internet Protocol (VoIP) relies on SIP for reliable call routing. Business VoIP often refers to the complete phone system for expanded telecom functionality like call recording.

If you have an IP PBX, you’re ready to take advantage of the scalability of SIP trunking.

All you need to use SIP trunking is access to manage your Private Branch Exchange (PBX). From there, simply add the credentials from your SIP trunking provider to connect it to the cloud.

Some PBXs might require extra setup. Nextiva provides free assistance to get you up and running. Nextiva is compatible with almost every IP PBX system, including Avaya, Asterisk, Cisco, 3CX, FreePBX, and Mitel.

If you want additional DIDs, toll-free numbers, or call paths, let us know when we prepare your personalized quote.

You purchase call paths, so essentially, your PBX should be able to handle however many call paths you purchase. However, we do have usage limitations, please review our policy for that.

Often you only need one SIP trunk per team or location, however you will need to define the amount of sessions you need based on the amount of calls your business will receive simultaneously. For example, if you buy 20 sessions and set them up in one trunk, users under that trunk will only have the handling capability for 20 total calls in or out. Additional call attempts will hear a busy signal. Don’t worry though, we can help!

Yes, you can use any phone number with Nextiva’s SIP trunking service. The process of transferring phone numbers is known as porting. You can port landline, toll-free, cell phone, and VoIP numbers.

Nextiva offers free number porting with every account. For faster setup, we’ll provide you with temporary phone numbers until the port is complete.

Unlike Twilio's Elastic SIP trunking, there's no need to learn APIs or hire a developer to enjoy reliable IP telephony.

Primary Rate Interface (PRI) is a legacy technology that requires physical wiring from the local telephone company. It supports up to 23 concurrent calls per circuit.

SIP trunks offer greater flexibility than PRI by connecting calls over the internet using an internet connection. It handles as many concurrent calls as your PBX and bandwidth supports.

IT pros enjoy SIP trunk services because they maintain full control of their PBX and pair it with the scalability of the cloud. No on-site installation or troubleshooting obsolete hardware, either.

The bottom line is SIP trunking is the best alternative to analog phone lines. Nextiva’s reliable VoIP network connected more than 1 billion calls last year alone.

Yes, Nextiva offers simple and flexible SIP trunk pricing to meet your needs. For additional savings, you may qualify for a lower rate with an annual agreement.

Unmetered plans provide unlimited outbound and inbound calling in the United States, Canada, and Puerto Rico.

If you’re on a metered plan, you will pay the following month for usage, including inbound toll-free calls.

SIP calls work exactly the same way any phone call works. The only difference is you have to have an internet connection and you aren’t able to make more calls than you have purchased call paths.

Typically, SIP trunks use port 5060.

2 Billion+ Calls on our network
100,000+ Happy customers
1,000+ Global employees
The most successful brands trust Nextiva:
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Main advantages of SIP trunking

Checklist (Choose SIP trunking options only if you answer ‘yes’ to the following questions. Otherwise click here):

Differences between Hosted PBX vs SIP Trunking

Hosted PBX
SIP Trunking
Size of team
If you have a small or mid-sized team, and no investment in PBX hardware, it is best to go with a hosted solution (not trunking).
You currently have an investment in a PBX hardware component, trunking will likely be most cost effective for the short term. However, we always recommend a hosted solution so you can focus on running your business, not just your phone system.
Average line of service is $17.95.
Upfront costs can be expansive - $10-$1Million depending upon needs and size of business. The nice part about hosted services such as Nextiva is the price is predictable and there are no extraordinary up front costs, like with private PBXs.
Maintenance and technical management
100% predictable.
No way to calculate.
100% scalable.
100% scalable.
Call Quality
Nextiva guarantees service.
Nextiva guarantees service.
Nextiva guarantees service.
Nextiva guarantees service.

SIP trunking: pros and cons


  • Cost effective for teams with LOW call volumes. Only pay for what you use.
  • Makes sense for businesses who recently invested in premise-based equipment.
  • Hands-on for installation and maintenance, for those who know what they want.
  • Device and hardware agnostic.


  • May require knowledgeable IT experts to handle maintenance, outages issues, installation, and general technical support.
  • Not a viable solution for call centers or high-volume companies.
  • Requires PBX solution (hardware/software), which often comes with big upfront costs and ongoing investments.
Read more

The secret's out. Try the best SIP trunk provider today.

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