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What Is UCaaS? A Guide To Unified Communications as a Service

What is UCaaS?

Unified communications as a service (UCaaS) is a cloud-based communications platform that incorporates multiple communication capabilities on a single platform hosted by a cloud provider.

The “as a service” portion of the acronym refers to the broader category of “software as a service” (SaaS) which is an aspect of cloud computing, i.e., services that are hosted in the data centers that are built, operated, and maintained by companies such as Amazon Web Services (AWS), Google Cloud, Microsoft Azure, and many other companies.

Because unified communications (UC) is delivered “as a service” the UC software itself is hosted in a remote data center. The enterprise typically pays a monthly subscription (per seat license) to access the UC server software via an Internet connection, while the UCaaS application is itself installed on end user devices (desktop, laptop and tablet computers, as well as smartphones and other end points).

UCaaS typically replaces (though it may also complement) an enterprise’s on-premises deployment of a private branch exchange (PBX) phone system. Some unified communications vendors provide UC software that runs on-premises in what amounts to a telecom closet or data center.


What are the main features of UCaaS?

UCaaS is software that runs on the major operating system platforms (e.g., Windows, Mac OS) as well as the mobile operating systems (Android, iOS) and Web browsers. There are also many different types of purpose-built devices that support UCaaS from traditional desk phones to video terminals and conference room systems, to other types of endpoints.

Unified communications platforms, whether the application is hosted in the cloud or running on-premises, typically include the following features:


Voice calling (Telephony)

This includes well-known PBX features such as voicemail and call forwarding. Voice over Internet Protocol (VoIP) is used to enable voice calling in UCaaS, but there are options for connecting with the public switched telephone network (PSTN) in the UCaaS client itself.


Messaging and chat functionality

Messaging refers to both the text-based messages (and emojis, etc.) that can be exchanged within the unified communications client as well as to the broader set of messaging applications. Sometimes the terms chat and messaging are used interchangeably. More broadly, the messaging category includes SMS/MMS, as well as applications such as WhatsApp, Facebook Messenger, etc.


Email and calendar integration

Microsoft offers Outlook, which combines email and calendaring in a single application. Teams is its companion collaboration application, which also integrates with the Outlook calendar. Similarly, Google Workspace offers integrated access to email, documents, meetings, etc. Zoom and Webex have similar capabilities in their own clients.


Collaboration tools, including Video

This can include features such as file sharing, whiteboarding, videoconferencing, video chats, video meetings, webinars, etc. Collaboration capabilities are one area where some unified communications providers are looking to differentiate. For example, Zoom launched Zoom Docs which it claims provides more opportunities to collaborate with coworkers than Microsoft Word or Google Docs, to name two prominent examples.



The term "presence" shows when a device/individual is active and reachable on the network. Individuals can set their status to available, busy, offline, etc. Presence is typically integrated with the Calendar application, so an individual’s presence will automatically change based on their meetings, work hours, etc. This feature is particularly helpful in the hybrid/remote workplace.


Compliance with E911 regulations

This article provides a good overview of how E911 works and why it is important for enterprises to make sure their unified communications platform fully complies with all local, state, and federal regulations. This is a complex issue, so click here for No Jitter’s library of articles related to E911.


Data security, privacy, and encryption

Specific offerings may include end-to-end encryption and single sign-on. Some security standards include ISO 27001, SOC 2 and FedRAMP. Note that how the UCaaS provider handles corporate data is particularly important when it comes to generative AI and large language models (LLMs).



Enterprises should ask about how their UCAAS provider will ensure that their UCaaS offering is maintained if the UCaaS company itself experiences an outage Most UCaaS vendors offer service level agreements (SLAs) in which they contractually guarantee a certain level of availability. Five 9s reliability—99.999% availability—is the gold standard. Four 9s availability (99.99%) is also common. Check out this article for more on the reliability of unified communications.


Fixed-mobile Convergence

This term basically means that the full UCaaS application experience is available in an application on an individual’s mobile device (e.g., smartphone, tablet). There have been various attempts at delivering this functionality, as this article details.


Third-Party Integrations

This includes APIs for allowing the platform to integrate other applications like third-party cloud storage, etc. In short, APIs allow the unified communications platform to integrate into other enterprise systems, including, but not limited to, workforce automation, sales force automation and contact/call centers.


Generative AI-powered Assistants

The inclusion of generative artificial intelligence (AI) into the products will provide various functionalities, including assistance in creating content (email, documents, whiteboarding, etc.) and summarization (of meetings, documents, etc.).


Leading UCaaS Providers

Some leading UCaaS providers include Microsoft Teams, Zoom, Webex, 8x8, Dialpad, Google, GoTo, Vonage, Sangoma and RingCentral. Check out this guide on how to choose a UCaaS provider for your business.


How does UCaaS work?

As mentioned, UCaaS is a subscription-based service that is run by the UCaaS provider. The application servers reside in the provider’s own data center (which could be private or leased from another company) or on public cloud platforms (e.g., AWS, Google Cloud, or Microsoft Azure). These options are typically referred to as:

  • Single-tenant: Each customer has its own dedicated software instance. Think of this as a company leasing an entire office building for its own dedicated use.
  • Multi-tenant: Multiple customers use the same software instance. Think of this as multiple companies leasing floors within an office building. They are sharing the overall infrastructure, but each company has a dedicated floor.
  • Hybrid: The UCaaS provider would run its software on their customer’s hardware. Think of this as the company owning the building but allowing some vendors to come inside their building and provide services.


Apps and Endpoints for Unified Communications

The software client is downloaded to the customer’s device (laptops, smartphones, etc.), and the UCaaS capabilities are typically accessible through Internet browsers. There are also endpoints—phones, videoconferencing equipment (Microsoft Teams Rooms, Zoom Rooms, Cisco Webex Rooms) – from a variety of vendors that allow the UCaaS features to be accessed in meeting rooms and other spaces.

Why use UCaaS?

There are several reasons to use UCaaS:

  • Cross-platform: UCaaS runs across operating systems (and devices), which helps make deployment easy.
  • Support for many device types: UCaaS software runs on computers and mobile/portable devices, but it can also integrate with desk phones and meeting room audio-visual equipment.
  • Service-based: Because UCaaS is a service, the spending is usually classified as “operational” rather than “capital,” meaning that the enterprise can (potentially) avoid the capital cost associated with buying a lot of expensive computing equipment and employing the IT staff to install and maintain it.
  • Support for hybrid work: UCaaS allows employees full access to communications and data regardless of where they are (assuming they have a stable, fast broadband Internet connection).
  • Scalability: Because UCaaS is software- and service-based, it is relatively easy to add (or remove) users from a UCaaS platform. This does require IT personnel to administer, add/remove/provision licenses and devices, configure permissions, etc.
  • Security: The UCaaS provider handles most security issues, updates, and patches to protect the overall service from attacks, etc. The enterprise may want to layer additional security services on top of what the UCaaS platform provides. The various UCaaS providers may differ in the types of security features they offer, and sometimes these features are gated behind price tiers.
  • New features, faster: The inclusion of generative AI-based functionality is a good example. The UCaaS provider will routinely add new services to their platform. Microsoft added Copilot to all its products, but it comes with an additional service fee. By contrast, Zoom added AI Companion to its UCaaS platform, but it is included with all paid plans.


What are the benefits of UCaaS?

Most of the benefits associated with adopting UCaaS were mentioned above as reasons to move to a UCaaS platform. There are several additional benefits, as well, that arise from those features.

Ease of Use

UCaaS relies on software, end user devices, and a connection to the cloud service provider. The software is typically intuitive and easy for most people to use, wherever they are located.

Lower costs

As suggested above, an organization moving from an on-premises phone system can potentially save some costs by standardizing on a UCaaS provider. Some of the avoided costs may involve limiting the need for additional on-staff IT personnel, purchasing/upgrading server hardware, managing a telecom closet or data center, etc.

Cost shifting

The UCaaS provider manages the server hardware and software, along with security updates, rolling out new features, etc. This doesn’t absolve the company’s IT staff of all responsibility, however. They still must manage the licenses, data permissions, features available to users (or a subset of users). And, there may be other security issues the IT staff needs to address.


What are the cons of UCaaS?

There are several cons associated with moving to UCaaS:

Choosing the right platform

There are many providers, each with the same basic features, but their implementation and/or interoperability may vary. For example, if Company A standardizes on Microsoft Teams, but their main supplier, Supplier B, uses Webex, then an extension is required in both apps to enable their interoperability. If not, then users in either / both companies may need to run both UCaaS applications side-by-side which can lead to the problem of “Shadow IT.”


Scaling the solution up (or down) is easier with UCaaS because it is license-based. But, enterprises can potentially waste dollars on unused licenses if they do not have a (telecom) expense management system. Check out this article on mastering telecom expenses.

UCaaS needs to connect to the PSTN to make “plain old” telephone calls. If that is not done, or not done correctly, then there could be business issues. This challenge is described in the previous section.


Note that with the rise of remote work, VoIP and unified communication services have emerged as a prime target for hackers. To reduce the likelihood of a successful attack, enterprises should reevaluate their existing defense strategy, starting with implementing behavioral analytics and machine learning technology. Security is an ever-present concern. The UCaaS provider should be transparent about how it protects against a variety of attacks.


Key UCaaS Trends

As mentioned, generative AI capabilities are being integrated with UCaaS. Many UCaaS providers are attempting to differentiate by also rolling out contact center as a service (CCaaS) capabilities, which are also discussed here in the context of CX and in this article, as well. Check out this article for an overview of the trends that will dominate the unified communications market in 2024. 



UCaaS, or Unified Communications as a Service, offers numerous benefits, including ease of use and cost savings. In general, the software offers workers an easy way to communicate and collaborate with colleagues inside and outside their company. From an IT perspective, unified communications software can help the organization save costs by eliminating the need to purchase and/or maintain on-premises systems. There are challenges associated with adopting UCaaS, one of which simply involves selecting a provider among the many options. Scalability is a key advantage, but without proper management, it can result in wasted resources. Additionally, security is a concern (as it is with any technology solution), especially with the rise of remote work.

No Jitter has an extensive library of articles on unified communications as a service. This article discusses Zoom and its new AI Companion, while this one provides an overview of Microsoft 365 Copilot, which is embedded in Microsoft’s unified communications and collaboration product, Microsoft Teams.

Corporate sustainability goals can also be furthered by moving to unified communications. Moving to UCaaS requires advance work that will help “jump start” the implementation process by having pre-assembled much of the critical information that would be asked of your company.

For all of No Jitter’s UCaaS coverage, click here.