📞 FusionPBX: the multi-tenant open-source PBX built on FreeSWITCH
A free, open-source web interface for the FreeSWITCH telephony engine, maintained by FusionPBX LLC in Idaho since 2008. Not a hosted service: IT teams, ITSPs, or integrators install FusionPBX on a Linux server, connect a SIP trunk, and manage it themselves. Its defining feature is native multi-tenancy, letting one server host many separate companies.
⏱ 9 min read · 🌍 Open-source PBX platform · 📅 Updated July 2026 · 🔗 fusionpbx.com
🧭 On this page
🏢 What FusionPBX is
📦 What FusionPBX offers
⚖️ Quick compare with two PBX rivals
👥 Typical adopter profiles
🎯 Where FusionPBX stands apart
📚 Terms you can look up
🧩 Decision tree
🔎 Other providers worth considering
❓ Common questions
📍 Next steps
🏢 What FusionPBX is
FusionPBX is a free, open-source web interface and application layer for FreeSWITCH, the telephony engine that handles the actual calls. It turns a Linux server into a full business phone system: extensions, dial plans, IVR menus, call queues, voicemail, conference rooms, and desk phone provisioning, all administered through a browser. The project started in 2008 and is developed by FusionPBX LLC, a company based in Eagle, Idaho, led by founder Mark J. Crane. The source code is available under the Mozilla Public License 1.1.
What sets FusionPBX apart from most open-source PBX projects is native multi-tenancy. One server can host many separate companies, each with its own domain, users, and call routing. This makes it a popular platform for internet telephony service providers (ITSPs) and managed service providers who build white-label voice services on top of it. FusionPBX is not a managed service and not a telecom operator: it supplies no phone numbers, no SIP trunks, and no call minutes.
📦 What FusionPBX offers
FusionPBX is free software plus an optional paid membership programme. The main components:
🖥️ Browser-based administration for FreeSWITCH
The core value of FusionPBX is that administrators do not need to write FreeSWITCH configuration by hand. Extensions, gateways, dial plans, IVR menus, queues, ring groups, voicemail, and phone provisioning are managed through a web interface with granular permissions. The underlying FreeSWITCH engine remains fully accessible for custom logic, often written in Lua scripts.
🏢 Native multi-tenancy on one server
Multi-tenancy is built into the core, organised by domain. Each tenant gets its own extensions, routing, recordings, and settings while sharing one server. This is the main reason ITSPs and hosting providers choose FusionPBX over single-tenant alternatives such as FreePBX. For a single business, the same architecture cleanly separates branch offices or subsidiaries.
🧩 Free core plus paid memberships
The software itself is free to download and run, with an installer for Debian, Ubuntu, and other systems. FusionPBX LLC sells optional memberships in four tiers: Green at 100 dollars, Blue at 300, Purple at 500, and Gold at 1,000 dollars per month, each with a 12-month commitment. Memberships add training, member documentation, advance security notices, white-label rights, member-only applications, and between 0 and 6 support hours per month. Notably, the JSON REST API sits in the higher membership tiers.
🔌 Bring-your-own SIP trunk and infrastructure
FusionPBX includes no phone numbers or minutes. Calling requires a SIP trunk from a carrier; in Luxembourg this is typically Mixvoip, Post Telecom, or Cegecom. The deploying team also supplies the server, backups, monitoring, and security hardening. The installer bundles fraud-protection basics, and version 5.5 shipped an updated Event Guard intrusion tool, but keeping an internet-exposed SIP system safe remains the administrator's ongoing job.
🤖 Recent releases add AI-assisted features
Version 5.5, released in January 2026, added call recording transcription and summary hooks, text-to-speech voicemail greetings, and WebSocket-based live dashboards. The administrator connects and pays for the underlying speech services separately. The release pace and a GitHub history of more than 24,000 commits show an active project.
⚖️ Quick compare with two PBX rivals
FusionPBX is an open-source PBX platform. This page compares it against two products a Luxembourg business or IT partner might shortlist alongside it.
🧬 FusionPBX
Multi-tenant FreeSWITCH GUI · this page
You are here
Deployment: self-hosted or hosted by partner
Licensing: free (MPL 1.1), paid memberships optional
Sold via: community and integrators
SIP trunk: bring your own
Teams integration: custom SBC build
Typical size: ITSPs and 10 to 500+ users
🧩 FreePBX
Asterisk with a GUI
Deployment: self-hosted or hosted by partner
Licensing: free (GPLv3), paid commercial modules
Sold via: community and certified partners
SIP trunk: bring your own
Teams integration: via commercial module
Typical size: 10 to 500 users
💻 3CX
PBX software
🔗 3cx.com
Deployment: self-hosted or 3CX-hosted
Licensing: annual, per simultaneous call
Sold via: IT partners and MSPs
SIP trunk: bring your own
Teams integration: via connector
Typical size: 10 to 500 users
Comparison reflects public information. Sources linked from each provider page. Not a ranking.
👥 Typical adopter profiles
FusionPBX is adopted by technical teams rather than bought by SMEs as a finished product. Four common profiles:
🤝 The ITSP or MSP building a voice platform
A telephony provider or managed service company hosting many customers on shared infrastructure. FusionPBX fits because multi-tenancy is native, licence costs are zero at any extension count, and white-label rebranding rights come with the membership programme. This is the platform's home turf and its most common professional use.
👨💻 The IT team with Linux and VoIP experience
An internal IT function comfortable with Linux administration, firewall management, and SIP. The browser interface covers daily administration, while direct FreeSWITCH access remains available for custom call logic. The team owns the server, the updates, and the security posture in exchange for full control and no per-seat fees.
📞 The workflow-heavy or custom deployment
A contact centre or specialist operation where commercial PBX products fall short. FusionPBX exposes queues, dial plan tools, and scripting hooks that let an engineer build bespoke call flows. The trade-off is that every custom script becomes something the organisation must document and maintain.
🔄 The business re-evaluating a self-hosted system
An organisation already running FusionPBX, often after the engineer who built it moved on. The choice is usually between recommitting with a paid membership or a hosting partner, and migrating to a managed Cloud PBX where the provider carries the operational load. IT capacity and growth plans typically decide it.
🎯 Where FusionPBX stands apart
Three positioning points worth weighing before adopting FusionPBX rather than a managed service or a commercial product.
🏢 Multi-tenancy that most rivals lack
Among open-source PBX platforms, native domain-based multi-tenancy is FusionPBX's signature. FreePBX is single-tenant by design, and commercial products charge per instance or per seat. For anyone hosting several companies, or several strictly separated business units, on one system, FusionPBX solves a problem the alternatives handle awkwardly.
💸 Free licence, real operational cost
The software costs nothing at any scale, and there are no per-seat fees. A running phone system is another matter: the honest total includes the server, the SIP trunk contract, security hardening, monitoring, upgrades, and skilled administration time. Optional vendor support starts at 300 dollars per month with a 12-month commitment, runs from a US time zone, and is English only. For organisations with real engineering capacity the trade can work; for a typical SME the time cost usually exceeds the licence savings.
🛡️ Everything an operator provides, you assemble yourself
FusionPBX is software only. Numbers, porting, emergency call routing, SLA, fraud monitoring, and support in local languages all come from elsewhere or not at all. In Luxembourg the numbers and trunk come from a local operator, the hosting from a cloud or server provider, and the accountability from whoever the business hires to run it. A managed Cloud PBX bundles all of this into one contract.
📚 Terms you can look up
Not sure what something on this page means? The pbx.lu glossary explains each in plain language.
🧩 Decision tree
Two honest recommendations based on what the organisation actually needs.
✅ Self-host FusionPBX if
- You are an ITSP, MSP, or integrator hosting multiple tenants on one platform
- You have an IT team or partner fluent in Linux, FreeSWITCH, and SIP security
- Zero licence cost at high extension counts outweighs the administration time
- You need custom call logic or scripting that commercial products cannot accommodate
- A paid membership for support and the REST API fits your budget if requirements grow
🟡 Use a managed service if
- You do not have dedicated VoIP engineering capacity, or it is better spent elsewhere
- You want numbers, porting, PBX, and support from one provider on one invoice
- Predictable per-user monthly cost matters more than licence-free software
- Support should answer in French, German, or Luxembourgish during local hours
- Security, patching, and updates should be the provider's job, not yours
🔎 Other providers worth considering
If self-hosting FusionPBX is not the right path, these are the logical next pages to check.
Same category · other PBX products and UC platforms
☁️ Voxbi
Managed Cloud PBX from Mixvoip, published pricing, Luxembourg-hosted
Different category · Luxembourg operators and SIP trunks
📦 Post Telecom
Incumbent national operator, SIP trunks and hosted telephony
❓ Common questions
What is the difference between FusionPBX and FreeSWITCH?
FreeSWITCH is the telephony engine: the software that actually connects calls, plays voicemail, and routes traffic. FusionPBX is a web-based administration layer built on top of it. FusionPBX lets administrators configure the system through a browser instead of editing FreeSWITCH configuration files by hand. Both are open source and self-hosted.
What is the difference between FusionPBX and FreePBX?
Despite the similar names, they are separate projects on different engines. FreePBX is built on Asterisk and is single-tenant by design. FusionPBX is built on FreeSWITCH and is multi-tenant by design, so one server can host many separate companies. FreePBX has a larger community and hardware ecosystem; FusionPBX is the more common choice for ITSPs and hosting providers.
Is FusionPBX really free?
The software is free to download and run, with no per-seat fees. Optional memberships cost 100 to 1,000 dollars per month with a 12-month commitment and add training, member-only applications, white-label rights, and between 0 and 6 support hours per month. The full running cost also includes the server, a SIP trunk contract, and skilled administration time.
Does FusionPBX include phone numbers?
No. FusionPBX is software only and is not a telecom operator. Numbers, minutes, porting, and emergency call routing come from a separate carrier connected over a SIP trunk. In Luxembourg this is typically a local operator such as Mixvoip, whose trunks are compatible with FusionPBX and FreeSWITCH.
Does FusionPBX integrate with Microsoft Teams?
Not natively. Connecting Teams users requires Microsoft's Direct Routing model with a separately licensed session border controller, built and maintained by the deploying team or an integrator. That adds cost and skills that should be priced into any comparison with platforms offering a packaged Teams path.
Can I migrate from FusionPBX to a managed Cloud PBX?
Yes. Luxembourg numbers are portable under ILR rules, and the carrier holding the numbers arranges the port. Extensions, IVR menus, and queues are rebuilt in the new platform, usually by the incoming provider's onboarding team. Custom dial plan logic and Lua scripts are deployment-specific and need rebuilding rather than transferring.
Is FusionPBX secure?
FusionPBX is as secure as the team running it. The installer includes fraud-protection basics and version 5.5 updated the Event Guard intrusion tool, but any internet-exposed SIP service attracts brute-force attacks and toll fraud attempts. Patching the OS, FreeSWITCH, and FusionPBX itself, restricting SIP access, and monitoring around the clock are the administrator's ongoing responsibilities. A managed Cloud PBX shifts these to the provider.
📎 Explore next on pbx.lu
📍 Next steps
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