Choose the powerful 3CX phone system from the UK's leading provider.

Enable true modern telephony for your business at a fraction of the cost. 3CX from Gradwell is an end-to-end solution, supported by the experts.

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SIP trunking products for businesses of all sizes


3CX tested and certified SIP trunks.

Direct Routing

Use Microsoft Teams as your business phone system.

High volume

Best-in-class contact centre functionality. 

The 3CX phone system provider of choice for UK businesses

Get the VoIP tech you need for less.

3CX is a flexible, intuitive, and feature-rich VoIP phone system. It’s a great choice for businesses of almost any size thanks to its enterprise-level features coupled with cost-effective pricing – based on concurrent calls, not charged per user.

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Flexible, powerful telephony

As one of a handful of Titanium-level 3CX partners, we’re recognised for helping thousands of users get the most out of 3CX. For a seamless experience, let us provide everything you need including hosting, SIP, support and hardware.

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Significant cost-savings

Base your license costs on the number of simultaneous calls - not the number of users or extensions – making our 3CX pricing more competitive than a charge per user model. Add in Gradwell SIP and connectivity for the ultimate, all-inclusive 3CX package.

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World-class experience

Thanks to personalised onboarding and Gradwell’s market-leading hypercare, you receive an unparalleled experience when implementing and using the 3CX phone system. 

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Secure and reliable systems

Our infrastructure leverages the full power of the cloud, hosted in a highly resilient environment (Google Cloud Platform). All enterprise 3CX systems are comprehensively backed-up to a secondary, geo-resilient data centre, delivering a 99.999% uptime SLA.

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Direct Routing

Use Microsoft Teams as your business phone system.

Direct routing is the process of using SIP trunks to connect Microsoft Teams to the traditional phone network (PSTN). With Gradwell’s SIP, you can turn Teams from a powerful internal communication tool to a full-scale unified communications platform.

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Low installation fees and monthly costs

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Flexible numbering and porting services

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Add advanced telephony features with Wave Teams+

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High-volume SIP

SIP trunks for contact centres.

We have designed our own high-volume SIP trunks specifically for customers needing high call-per-second and high channel capacity. With unlimited inbound SIP, expect no delays in call connection, even at peak times. Integrating directly with your existing PBX, our high-volume SIP Trunks allow you to take advantage of cloud-based solutions, without replacing your existing equipment.

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Pay as you go and blended minute bundle options available

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No delays in call connection, even at peak times

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Performance tested with all major PBX vendors

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Streamline your business with the UK’s leading 3CX phone system provider

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"3CX offered the modern VoIP solution that we were looking for and Gradwell could provide the cost-effective option of scaling the system based on SIP lines rather than physical handset.”

Erin Tuecher, 

Deputy Head of IT 

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“Gradwell were by far and away the best value for money quote that we received, the Gradwell pricing structure is just phenomenal – such a massive difference from some other providers, and together with their exceptional service levels, it really was a no-brainer.”

Chris Goodchild,

General Manager

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“We are so lucky that we found you guys and it has transformed our service and has absolutely made the service what it is today. It has transformed care for countless numbers of people in Northeast London.”

Richard Muswell,

Service Digital Lead

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Award-winning service from the leading 3CX partner

Expert support

Access to more 3CX-certified engineers than any other UK business.

Recommended SIP

Our SIP services are recommended by 3CX, so you get reliable, trusted connections.

Customisable systems

Extend the power of your 3CX installation with custom integrations and wallboards.


Our experts answer your most common questions about our 3CX service.  

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What are some of the key features of the 3CX phone system?

3CX includes an extensive list of features, in line with market-leading phone systems. Gradwell customers also benefit from an easy-to-use web interface, integration with your CRM and external communication platforms such as Facebook, WhatsApp, SMS and web chat.  

What’s the difference between a 3CX phone system and my current on-site PBX? 

3CX is typically deployed as a cloud-managed service in a data centre, rather thanas a physical on-site PBX. This removes the risk of any expensive repairs,offers a range of extra features and eliminates the need for any additionalmaintenance contracts.

Can I transfer my existing business number to Gradwell?

Yes – as long as we have a porting agreement in place with your current provider, we will be able to move over your business numbers, if required. Our experienced support team will complete the necessary porting documentation and manage the order through to completion.

Can I get 3CX on my mobile phone?

Porting numbers can take up to two weeks depending on how many you have. We will request it as soon as possible and inform you when your number has been ported.

I'm not sure if I have a good enough internet connection for SIP.

Gradwell has a wide range of connectivity options available that are suitable for running our SIP trunking services over. In just a few questions, our team will be able to advise which connectivity option is suitable for your business.

Why Gradwell?

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Expert support

Receive as much or as little help as you need from our dedicated UK support team – 24/7/365 – and only pay for what you need.

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Born in the cloud

We’ve always engineered our solutions in the cloud, benefitting from decades of experience plus learning and responding to the market.

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Secure & compliant

Enjoy total peace of mind thanks to our ISO 27001:2013 certification, Microsoft Gold Partner and 3CX Titanium Partner statuses.