10 Open Source Call Center Software Options & Better Alternatives

So you’re contemplating using open source call center software? It’s cheap, full of functionality, and compatible with the public cloud, so what’s not to like?

In this blog post, we introduce 10 open source call center options and explore the pros and cons of going open source versus investing in market-leading alternatives.

What Is Open Source Call Center Software?

Open source call center software is free to use, customizable to the nth degree, and backed by a community of developers. Popular in large businesses with in-house expertise and small businesses familiar with coding and development, open source call center software solutions are often favored over proprietary software.

What is the difference between open source and proprietary call center software?

Open Source Call Center Software	Proprietary Call Center Software
Free to download	Subscription-based
Extremely customizable	Somewhat customizable
Backed by a community of developers	Supported by documented SLAs and dedicated support teams
Security depends on community updates and maintained interest and usage of the product	Vendor-managed security with strict protocols and regular updates
Scalable with the help of expert developers and external project management	Easily scalable thanks to vendor resources and infrastructure

How does open source software handle inbound vs. outbound calls?

Open source software handles inbound and outbound calls similarly to proprietary software. When an inbound call reaches your call center, open source software uses preconfigured call routing rules and features like interactive voice response (IVR) and auto attendants to send customers to their desired destinations.

Outbound calls work in the same way. When a call center agent needs to make a call, they use their dial pad, call history, or contact list, and a SIP trunk powers the call over the internet.

Can open source call center software integrate with existing CRM systems?

Open source call center software is highly customizable and can be integrated with any customer relationship management (CRM) system that has publicly accessible APIs. However, programming the integration may require in-depth knowledge, so you may need help from both the CRM provider and the open source community.

What are the risks associated with using open source software?

When using open source software, you’re forfeiting the right to an agreed SLA and a vendor with plans for redundancy and resiliency. You also lose the benefit of having a dedicated technical support and/or account management team.

For enterprises or businesses that rely on their call center software for sales or support, this may be a turnoff because there is no guaranteed fix time or credit agreement if something goes down.

The Open Web Application Security Project has documented its 10 major concerns about relying on open source software for business-critical functionality:

• Known vulnerabilities
• Legitimate package compromise
• Name-confusion attacks
• Unmaintained software
• Outdated software
• Untracked dependencies
• License and regulatory risk
• Immature software
• Unapproved change
• Software bloat

It’s also a major risk to introduce open source software if you have agents or users who are accustomed to modern interfaces. While free and full of functionality, open source projects often lack the budget and time to develop a friendly front end that anybody can use with zero training.

Take VICIdial, for example. It’s an eyesore and doesn’t lend itself to usability.

Why choose open source software for a call center?

Despite the potential risks associated with open source call centers, they remain popular for their scalability, flexibility, and cost-effectiveness. For businesses that prefer cheap and flexible solutions rather than secure and resilient ones, open source software provides a cost-effective option without the need to commit to a proprietary vendor, sign a contract, and incur the associated costs.

Is open source call center software worth it?

Open source, free call center software is worth it when:

• You have minimal or no money in your budget for up-front costs
• You have highly experienced in-house developer resources
• You plan to build a highly customized solution unique to your business

It’s not worth it when:

• You consider your call center to be the front line of your business
• You have a support or sales function that depends on inbound calls
• You value security and redundancy over cost and customizability
• You have many agents who are used to intuitive and graphical interfaces

Key Features of Open Source Call Center Software

When looking into open source call center software, expect to come across these key features:

• Call routing: This type of software has various options for creating call paths that get customers to the most suitable agents for their queries. Features like IVR, auto attendant, and automatic call distribution are widely used to speed up the connection to agents.
• Call recording: All (or some) calls are recorded and stored in the cloud for compliance, training, and monitoring purposes. The calls can be downloaded locally or sent via email.
• VoIP and telephony: Some open source call centers may also provide the underlying VoIP service to enable outbound calling and transfer inbound calls from software to agents.
• SIP trunking: Open source software that doesn’t have its own VoIP service may offer SIP trunking to a supported carrier.
• Omnichannel support: Open source software has additional digital channels like SMS, email, web chat, social media, and WhatsApp so customers can contact you through their preferred method.
• CRM integrations: Mature open source software may have pre built integrations. Other software may require extensive API and SDK programming to achieve a two-way information exchange between back-end and front-end systems.
• Real-time analytics: Open source software has analytics tools that report the volumes, patterns, and behaviors of customer calls and assess agent performance.
• Dialer types: Some open source call centers may provide options like auto dialers, power dialers, and predictive dialers.
• Desktop and mobile softphones: Some open source software is also accessible via a mobile app or site in recognition of the uptick in remote work.

Related: Call Center Recording Software Pros, Cons, and Use Cases

Top 10 Open Source Call Center Software Options on the Market

Let’s take a look at the top options for open source call center software, their key features, and why it might be right for you.

1. Asterisk

Asterisk is a widely used open source PBX framework with call center components available as add-ons. Businesses often start with a basic phone system and add a third-party call center or delve further into its call center capabilities.

Key features

• Call queues and IVR
• Live monitoring and reporting
• Can be built using a single Asterisk server or deployed from a turnkey IP PBX

Why choose Asterisk?

• Customers think of Asterisk as a flexible VoIP platform that allows interaction with telephone systems and integration with specific business applications.
• Customers also love Asterisk’s cost-effectiveness, saying, “You can buy really cheap analog lines and hook up to this system.” If you’re not overly technical, this sometimes makes up for the time it took to configure your initial setup.

2. Elastix

Elastix, now owned by 3CX, features three types of call center modules in its GitHub resources: start-ups, teams, and enterprise. Each of these introduces more enhanced functionality as you level up. You can also opt for a prebuilt, industry-specific package like health care, finance, or manufacturing. The more functionality you need, the more you pay — as you would with a traditional SaaS call center.

Key features

• Predictive dialing
• Campaign without agents (a future feature release)
• Built-in Erlang calculator

Why choose Elastix?

• Users enjoy the built-in softphone for Mac and Windows.
• Some customers say they’ve halved their phone bills by using Elastix.

3. FreePBX

Unsurprisingly, FreePBX’s main draw is that it’s free. However, the word “free” in its name stands for “freedom,” and getting set up for anything more than basic PBX functionality comes at a cost. 

You can download the software directly to your browser or PBX and get started in minutes if you opt for the most basic installation. FreePBX comes with pre-made training and support materials that are accessible to the public. There is a wide range of associated products available via FreePBX, like IP phones, video conferencing, and connectivity.

Key features

• Extensive wiki and documentation
• Fax to email service
• International language support

Why choose FreePBX?

• Community members suggest 90% of the setup is “set and forget.”
• Customers find that FreePBX is a full-featured open source option for enterprise if you have the expertise or are willing to learn.

4. FusionPBX

FusionPBX is a versatile open source software that can also double as a fax server, VoIP server, voicemail server, or conference server. If you’re looking to go open source across the board, installing all components and managing them from a single pane of glass portal is easy.

Key features

• Modern supervisor interface when integrated with QueueMetrics
• Multilingual transcription and translations
• Traditional on-premises functionality like paging and fax

Why choose FusionPBX?

• Users describe the monitoring and control over active calls as second to none.
• Customers also say it’s amazingly fast to set up and run.

5. FreeSWITCH

FreeSWITCH is predominantly an open source phone system with the addition of some basic call center features. You can manage voice, video calling, and data in a single line when using FreeSWITCH as a call center solution. 

Key features

• Automatic call distribution
• Busy call retry for outbound campaigns
• CDR reporting (on issues including what time a call started ringing, how long the talk time lasted, how long the phone rang, and how long the call was on hold)

Why choose FreeSWITCH?

• FreeSWITCH has a reputation for high stability and reliability.
• It was built by a former Asterisk developer who identified multiple issues with Asterisk.

6. Incredible PBX

Incredible PBX is an open source project that provides all the components you need to build your own unified communications solution. You can deploy Incredible PBX with on-premises hardware including Raspberry Pi, in the cloud on a variety of platforms, or on virtual machine platforms like VirtualBox, VMware, and Proxmox.

Key features

• Text to speech and speech to text
• Digital channels like SMS and fax
• Support for ChatGPT

Why choose Incredible PBX?

• There’s an active community of users, and support is provided for people with paid memberships.
• Users say it provides “rock-solid security” by using the Asterisk base.

7. Issabel

Issabel is an open source IP phone service that comes with add-on contact center software that enables you to manage incoming calls, automate outbound call center activity, and benefit from a bespoke Linux-based training program for users.

Key features

• Combines voice, text, and social media in a single agent interface
• Integrates with WhatsApp, Telegram, and Facebook
• Integrates with voice synthesis engines

Why choose Issabel?

• Reviews suggest easy and quick installation.
• Former users of Elastix like Issabel’s similar look and feel.

8. GOautodial

GOautodial is one of the more user-friendly open source call centers. It has a simple interface for managing calls, handling inbound calls, and setting up outbound campaigns. It also comes with more out-of-the-box features and less configuration than traditional open source software.

Key features

• Omnichannel support, including voice, text, web chat, email, and social media
• Built-in CRM software
• Built-in ticketing and helpdesk system

Why choose GOautodial?

• It runs on high-availability servers located on the East and West coasts. 
• Its data centers are SSAE 16 SOC 1- and SOC 2 Type 1-certified and HIPAA- and PCI DSS-compliant.

9. VICIdial

VICIdial claims to be the most popular open source contact center solution in the world. However, its website hasn’t been updated since 2016. 

Customers choose VICIdial when they don’t have the in-house infrastructure or resources to host their own on-site equipment. Instead, the Vicidial Group’s VICIhost service creates dedicated servers for them in its cloud.

Key features

• Multichannel support for voice, email, and web chat
• Scalability to one million calls per day
• Add-on time clock to track agent activity

Why choose VICIdial?

• It has a footprint in over 100 countries.
• Setup is fast, and a free, cardless trial is available.

10. Linphone

Linphone isn’t a call center; it’s a popular open source VoIP/SIP softphone that facilitates calling and messaging. That means there’s no dedicated call center functionality. However, it does have the ability to provide a switchboard and make attended call transfers.

Key features

• Switchboard/operator console
• Warm, attended transfers
• Inbound and outbound voice

Why choose Linphone?

• When compared as a free alternative, it is recognized as a good SIP softphone with important missing features.
• The vast majority of users cite its ease of setup and management.

Top 5 Best Call Center Software Providers

If you don’t like open source solutions, here are the top five call center software providers, their key features, and why it might be right for you.

1. Nextiva

When you’re considering proprietary call center software, look no further than Nextiva. Why choose Nextiva over an open source solution?

First, take a look at the interface. 

Isn’t this what you want your agents to be using?

You’ve got voice, chat, SMS, email, and social media available on a single screen. There are clear notifications and task lists for agents to work from. Making and receiving calls is a breeze.

We’ve come a long way since the days when open source and blocks were the only options available for contact center agents. A familiar and intuitive interface will make agents more productive and speed up training time.

You also get considerably more support than in the open source world. That’s not meant as a criticism of any specific provider — it’s the nature of open source versus proprietary software.

With Nextiva, you get award-winning, 24/7 support. You can also reach a support agent via the method of your choosing — phone, email, or web chat. No matter how you reach out to us, we’re available when you are.

We’re not suggesting you’ll need us, though. With 99.9999% reliability, we’re one of the most efficient call center solutions you’ll find.

Our ready-to-use solution is employed by over 100,000 brands every day. They all benefit from regular updates and new features as part of a total package. There are no duct-taped integrations and no reliance on community support for feature requests or bug fixes.

Key features

• Intelligent queuing and callback
• AI-powered, omnichannel contact center
• Out-of-the-box integrations with apps like HubSpot, Salesforce, Zendesk, and Zoho
• Enhanced analytics with full customer journey orchestration

Why users like Nextiva

• Customers praise the “awesome” onboarding and fast response to setup issues.
• Customer service teams “don’t miss a beat.”

2. 3CX

Since acquiring the Elastix brand in 2016, 3CX has focused on its own toolset for PBX and call center functionality. Existing users have gotten accustomed to the interface and benefit from regular updates.

3CX partners are experiencing uncertainty and confusion regarding 3CX’s pricing, particularly around the cost of concurrent calls. This confusion is then passed on to customers, who may end up overpaying for their 3CX services.

In 2023, 3CX suffered a large data breach, exposing considerable flaws in its security and sending IT managers scrambling. Wired confirmed the breach was actually two linked attacks, causing concern among partners and customers alike.

Key features

• Supports voice, live chat, SMS, and WhatsApp
• Real-time wallboards and dashboards
• SLA alerts

Why users like 3CX

• Users report it’s a “really good product for basic business needs.”
• Users praise the company’s fast response to customer-facing website queries.

3. AVOXI

AVOXI is a global provider of voice connectivity and call center software. You can either go all in and get direct connectivity through its worldwide network or opt for the stand-alone call center module.

Key features

• Advanced call monitoring and analytics
• Genuine global coverage for complex deployments
• Key voice integrations with Genesys, Amazon Connect, Zoom, and Microsoft Teams

Why users like AVOXI

• Customers say, “All the staff are very helpful” with setups.
• One customer reports they have reduced their total cost of ownership while improving their customer experience.

4. CallHippo

CallHippo is a virtual phone system app that you can try for free. As you build your business, you can add contact center features like WhatsApp integration, a power dialer, and the ability to track the performance of live calls.

Key features

• Live call monitoring
• Answering machine detection
• Auto rotate feature (which displays a different phone number or caller ID for each outbound call to avoid spam markings)

Why users like CallHippo

• Users say the dashboard is “incredibly intuitive,” making it easy for teams to use from day one.
• Its support team provides fast and responsive resolutions.

5. Twilio

If you crave the customizability of an open source solution but need the safety of proprietary software, Twilio is the haven in the middle. Specifically, Twilio Flex enables businesses to pick and choose which type of functionality they need at any given time. However, its highly advanced features and flexibility come at a cost — both financially and in terms of the technical resources required to get it up and running.

Key features

• Unified agent experience
• DIY advanced routing capabilities
• Wide range of developer and integration tools

Why users like Twilio

• Twilio’s one-time password verification is “secure and seamless.”
• Introducing WhatsApp notifications for medical appointments is a neat use case.

Nextiva’s Call Center Software Solution

If you’ve read this far, then you’re going to want to take a look at Nextiva Contact Center. Our omnichannel tool delights more than 15 million users every single month.

Related: AI Call Centers: The Future of Customer Communication

Check out the top-ranked AI-powered contact center here. 👇