0330 122 3000




Introducing Simwood

We believe the convergence of telecommunications technologies can change the world for the better and we exist to enable that change. From developer-friendly APIs and human-friendly interfaces, to our unconventional approach to fraud protection, our IP exchange empowers our customers and champions a fair and transparent telecommunications marketplace.

We’ve spent 20 years ensuring we own or at least control every element of the infrastructure underpinning our service, to give businesses which share our outlook the best service levels and fastest access to new technology possible. Together we’ll out-innovate and out-deliver ‘me too’ to give your end-users what they deserve!

For Business


Technology moves fast, those waiting for a proven market move slowly. We not only embrace the latest developments and practices, you’ll find us speaking around the world and shaping them.

We think everyone deserves things such as strong encryption, and the latest - most efficient - codecs, and we’ll always likely be working on it before you need to ask!

You’ll also find us implementing and evangalising the latest networking and development technologies too usually 5-10 years ahead of ‘me too’, although of course they’ll tell you different.

We do this in a way that means despite innovating and evolving rapidly, we maintain probably the highest uptime in the industry - our last service outage was 2010.


Our honeypots have detected around 3.6m hack attempts in the last 12 months. This information, is used in real-time to protect our customers.

We also publish biennial analysis which is sought out by the very largest carriers in the world, and multiple agencies. This gives us an unparalleled address book to hear about the latest threats.

Of course, we also learn from it ourselves and ensure our service has the necessary knobs and switches to combat it.

We put extraordinary efforts in to preventing you spending money you don’t intend to. In our view, simply telling you after the event is as wrong as the fraud itself.


Our portal is designed to be powerful, full of functionality, but also easy to use. It represents 100% of the rich features in our API in a user-friendly form.

We want customers to be totally in control of our services and are often astonished at the war stories we hear about other operators.

No need to fill in paper forms or spend hundreds for a new SIP trunk for example - just do it yourself in seconds through our portal. The same is true for every other operation.


We’ve had an API since 1996, before they were even called APIs. To us it makes no sense for you to expend time filling in forms asking us to perform manual operations - that costs us both money and slows down delivery.

Via our API your developers can integrate us deeply into your own automated provisioning, fraud monitoring and billing processes. You’ll dramatically improve service agility for your customers and can focus on the value you add, rather than fitting in with our processes.


In a world of ‘cyber cloud 2.0’ a company that insists on owning and operating its own infrastructure probably seems odd. We do it for a reason and that reason is control of our service to you.

Rest assured, this doesn’t mean we’re old fashioned. On the contrary, you’ll find the same ground-breaking technologies underpinning the Simwood network as in the global cloud providers.

Because our network is a strategic asset that has to add value, we iterate and upgrade it frequently. It isn’t a collection of expensive ‘fridges’ working to pay for themselves!

Beyond IP, we choose not to be a reseller, and that means investing in yesterday sometimes to ensure we’re at the right place in the supply chain. We have Regulated Interconnects to the incumbent and others over technologies such as SS7 given these are not available over IP - whatever ‘me too’ may tell you.

For Engineers


We’re proud to be the amongst the first to implement new standards and technologies. Moreover, you’ll find us speaking at industry conferences and working at the heart of the communities we’re proud to be part of.

Our wholly owned network implements the best of modern software-defined practices - enabling multi-Terrabit throughput with total control in our software.

We also support the latest encryption standards to keep your customers' communications secure and private, and modern variable bit-rate codecs such as Opus to facilitate high quality audio across limited or variable bandwidth connections including mobile and fixed-wireless networks.


We provide many advanced tools to prevent and mitigate fraud, including the ability to monitor the value of calls in progress in real-time via our API to identify unusual traffic before the call ends.

We also provide an unparallelled range of controls allowing you to limit calls, or cost of calls, to certain destinations should an attack progress. Additionally, all customers benefit from our own unique real-time threat protection identifying known ‘test numbers’ - in some cases preventing the attack months before it would otherwise happen.

Our honeypot analysis is available in real-time through our portal and our world-regarded analysis of VoIP Fraud, whilst sought out by the world’s largest operators, is made available exclusively to customers first. The unparalleled address book that results from this is put to active use in staying ahead of the game.


Our web-based portal is built atop our API, and provides the same functionality in a user-friendly format. 

Ideal for configuring numbers, trunks, and our fraud prevention measures the portal also exposes the underlying API data of call statistics and CDRs in a more human-friendly way.

It is a quick way of getting going and identifying the areas you need to integrate with our API as you push towards automation.


Our developer-friendly JSON-based HTTP API allows full control over the services we offer.

The API enables you to provision and control numbering; including real-time call routing changes, number porting, as well as creating and configuring SIP trunks for customer outbound calling.

Additionally, you can monitor all aspects of your service - such as calls in progress - with simple API calls.


We insist on owning our own equipment, and operating our own network hardware across links that wherever possible we control down to the fibre in the ground.

‘Cloud’ has a place but we prefer to embrace the same leading network technologies in a network we control. You’ll see us talking at conferences about the latest technologies that leverage our Arista hardware with total software control

Our network is a living evolving thing, that is constantly under review as a value-adding strategic asset. We wouldn’t maintain hardware in 11 datacentres if there was not tremendous value added in doing so.


I can't recommend these guys highly enough. It's refreshing to work with a company full of competent people who are actively pushing the boundaries and innovating all the time. Not only this, but they're also by far the most reliable carrier we've had the pleasure of working with over the past 5 years.
If you are looking for a company who actually understands SIP then Simwood should be your first stop. We run a small telecoms business in the North West of the UK. Over the years we've been resellers and consumers of SIP services from most of the big players in the UK. When the **** hits the fan it soon becomes apparent who understand this stuff on a technical level and who doesn't. Speak to them, you wont be disappointed.
After dealing with Simwood over the last year, it's obvious they know what they're doing. Customer service is second to none, along with the flexibility provided by the portal/API, the bar has been set very high.
Refreshingly honest company to work with. Great for UK centric business (UK termination prices and coverage of UK DIDs is excellent). Wide range of price points that target both large and small customers. We are not a huge customer, but we do get individual attention even on the startup plan. You can always pick up the phone and speak to someone knowledgeable and any tickets are dealt with promptly.

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Simwood eSMS Limited
Simwood House
Cube M4 Business Park
Old Gloucester Road
BS16 1FX
United Kingdom

0330 122 3000

Registered in England 03379831

Simwood Inc
5016 Spedale Ct, Ste. 306
Spring Hill, TN 37174