Multi-Tenant PBX for MSPs: Hosted or Self-Hosted?

Tom Reed · Updated 25 October 2026

A multi-tenant PBX lets an MSP run phones for many business customers on one platform while keeping each customer's users, numbers and call flows separate. You can either let the provider host each customer for you, or run your own server with many tenants on it. Pick by how much server work you want to take on, where your customers need their data, and how you want to pay for seats.

This guide is for MSPs, ITSPs and VoIP providers deciding how to run voice for many customers at once. It stays vendor-neutral until the section on SessionPBX near the end. Teams Phone and Teams Business, mentioned there, are SessionPBX plans, not Microsoft Teams.

What is a multi-tenant PBX?

A multi-tenant PBX is one phone platform that holds many separate customer phone systems, called tenants. Each tenant has its own users, extensions, numbers, call flows and settings. The customers share the platform underneath, but none of them can see or change another customer's setup.

Think of it like a block of flats. The building, the lifts and the wiring are shared. Each flat has its own front door, its own key and its own layout inside. The landlord, in this case the MSP, can manage every flat from one office.

The alternative is a single-tenant setup: one PBX per customer, either as a box in the customer's comms cupboard or as a separate server or virtual machine you look after for each client. That works for a handful of customers. It gets harder as you grow, because every new client means another system to patch, back up, monitor and log in to.

You'll also see the term written as multitenant PBX or multi tenant VoIP. They all mean the same idea: many customers, one platform, each kept apart.

Why do MSPs need multi-tenant phone systems?

Most MSPs already run IT for many clients from one set of tools. They manage devices, email and security across every customer from a central place, with consistent policies and one way of working. A multi-tenant phone system brings voice into the same model.

The main reasons MSPs choose one:

• One place to manage every customer. Your engineers sign in once and can move between customers, rather than juggling a separate login and interface for each client's phone system.
• Consistent setup. You can build each new customer the same way: the same numbering pattern, the same call flow structure, the same admin roles. That makes support faster, because every system looks familiar.
• Growth without a box per client. Adding a customer means creating a new tenant, not buying, installing and maintaining another PBX.
• Cleaner offboarding. When a customer leaves, you remove or hand over one tenant. Nothing else on the platform is affected.
• Clear separation of responsibility. Each customer's settings, users and admins live in their own tenant, which makes it easier to say who can change what.

If you're still deciding whether to offer voice at all, start with our guide on whether your MSP should add hosted PBX. This guide assumes you've decided to sell voice and now need to choose how to run it.

Hosted or self-hosted: which multi-tenant model fits?

There are two main ways to run a multi-tenant PBX as an MSP. On a hosted platform, the provider runs the servers and you manage each customer's phone system through their portal. On a self-hosted platform, you run the PBX software on your own server and put many customer tenants on it.

Neither is better for everyone. The right choice depends on how much server work your team wants, where your customers need to be hosted, and how you want to be billed. Here's how the two compare, using SessionPBX as the example.

Hosted vs self-hosted multi-tenant

A few practical questions help you decide:

1. Do you have someone who wants to run a voice server? Self-hosting means patching, monitoring and fixing it when something goes wrong. If nobody on your team wants that job, hosted is the safer choice.
2. Do customers have hosting requirements? Some customers care where their phone system is hosted. A hosted platform with a choice of regions may cover them without you running anything. Others may want the system on infrastructure you control.
3. How do you want to pay? Hosted billing is usually monthly or annual. Self-hosted software is often licensed annually. Match this to how you bill your own customers.
4. Can you mix the two? Many MSPs do. Small customers go on the hosted platform with nothing to run, and customers who need the system on your own infrastructure go on your server.

The comparison is about where the platform runs and who maintains it. On both models you still own the customer relationship and do the day-to-day setup.

How are customer tenants kept separate?

Separation is the whole point of a multi-tenant PBX. Each customer should feel as if they have their own phone system, because in every way that matters to them, they do.

On a well-designed multi-tenant platform, each tenant has its own:

• Users and extensions. Extension 201 at one customer has nothing to do with extension 201 at another.
• Numbers. Each customer's numbers route only into their own tenant.
• SIP trunk. Each customer can have their own trunk from their own carrier account, so calls and charges stay with the right customer.
• Call flows. Business hours, IVR menus, queues and ring groups are built per customer.
• Admin access. Each customer's admins see and change only their own tenant.

Admin access is where separation most often goes wrong in practice. Decide up front who on your team can change every tenant, who at each customer can manage their own users, and who can only view settings. Our guide to phone system admin permissions has a simple role model you can reuse for each customer.

Per-tenant setup checklist

Use the same short checklist every time you add a customer:

1. Create the customer's tenant or project under your partner account.
2. Choose the hosting region for that customer, if the platform offers a choice.
3. Connect the customer's SIP trunk. Any SIP-compliant carrier, authenticated by IP or credentials.
4. Set up extensions and numbering. Reuse a consistent pattern across customers; our guide to the phone extension numbering plan shows how to design one.
5. Build the call flows for business hours, out of hours, queues and ring groups.
6. Set admin access for your engineers and the customer's own admins.
7. Add app logo branding if you're putting your logo on the customer's softphones.

Where is each customer's data hosted?

On a self-hosted platform, the answer is simple: wherever your server is. On a hosted platform, it depends on the regions the provider offers and whether you can choose a region for each customer.

Being able to choose per customer matters for MSPs. A customer with staff in one country and a customer with staff in another may want different regions, and you shouldn't have to run two platforms to serve them.

For SessionPBX hosted, the hosted PBX page puts it this way: SessionPBX is hosted in the UK (London), the US (New York) and Singapore. On the partner programme page, you choose where each customer is hosted: the UK (London), the US (New York) or Singapore, and each region has its own database.

Hosting region is only one part of data residency. Your customers may also ask where call recordings, voicemails and backups are kept, and who can access them. Our guide to phone system data residency covers the questions to ask, from your customer's side.

What do you need to self-host a multi-tenant PBX?

Self-hosting gives you control of where the system runs. It also makes you responsible for the server. Before you put customers on your own infrastructure, check you have the basics in place.

Before you self-host

1. A dedicated server that meets the vendor's published requirements. Check the current server requirements and deployment guide in the vendor's partner docs before you build anything, rather than sizing it from memory.
2. The network and remote access the requirements call for. Make sure your hosting or data centre provider can supply what the deployment guide lists.
3. Someone who owns server updates and monitoring. Name a person and a backup person. Updates, security patches and monitoring don't happen by themselves.
4. A plan for backups and recovery on your server. On a self-hosted system, backups are your job. Decide what you back up, where it goes and how you'd restore it.
5. Partner approval. Self-hosted options are often limited to approved partners, so apply and get approved before you promise self-hosting to a customer.
6. A plan for which customers go hosted and which go self-hosted. Write down the reason for each, so new engineers understand the choice.
7. A support plan for the server. Decide who gets alerted when something goes wrong out of hours, and how you'll tell affected customers.

If you can't tick the first four, start on hosted. You can move to self-hosting later, once your team is ready to run the server.

How do seat-based costs work across tenants?

Most multi-tenant phone platforms price by seat: you pay for each user or extension you put on the platform. Across many tenants, that means your cost grows with the seats you actually sell, not with the number of servers or boxes you run.

When you compare platforms, ask:

• What counts as a seat? Check whether it's a user, an extension or a device, and whether plans come with a base number of seats.
• Are hosted and self-hosted priced differently? Often they are, with different billing periods.
• Who bills the end customer? Ideally you do, so you control the price and the invoice.
• What other costs sit outside the platform? Your SIP carrier bills separately for numbers and calls. On self-hosted, your server, hosting and network costs are yours too.

For SessionPBX, self-hosted runs many customer tenants on your own server with every customer kept separate and priced per seat, so you pay for the seats you sell. Partner pricing applies to both hosted and self-hosted. You set your own price and invoice your customer. We don't list figures here because they can change: current partner pricing is on the SessionPBX Partner Programme page, and approved partners see self-hosted licence prices in the partner portal.

How does SessionPBX handle multi-tenant for partners?

SessionPBX is a business phone system from SessionTalk. The SessionPBX Partner Programme is for PBX resellers, managed service providers, IT companies and communications providers that sell phone systems to business customers.

Hosted or self-hosted, your choice. Let SessionTalk run it, or run it on your own server with multi-tenant for many customers. Partner pricing applies to both.

Hosted. SessionTalk hosts and maintains it and there's nothing to install. You choose where each customer is hosted: the UK (London), the US (New York) or Singapore, and each region has its own database. Each customer gets one SessionPBX project, created and owned by you. Hosted plans offer monthly or annual billing.

Self-hosted. Self-hosted is for approved partners only. You run many customer tenants on your own server, with every customer kept separate and priced per seat, so you pay for the seats you sell. Self-hosted uses annual licences.

Per-customer control. You manage extensions, numbers, the SIP trunk and call flows for each customer. SessionPBX is bring-your-own SIP trunk: you connect any SIP-compliant carrier by IP or credentials, and your carrier bills for numbers and calls. SessionPBX doesn't supply numbers or lines.

Security. SIP signalling, messaging and the admin portal use TLS, and stored SIP trunk credentials are encrypted with AES-256-GCM.

Branding. App logo branding puts your logo and in-app product name on the softphones. It's included with Teams Business and available as an add-on on Teams Phone. Teams Phone and Teams Business are SessionPBX plans, not Microsoft Teams.

Billing. You set your own price and invoice your customer. There are no commissions to chase and no payouts to wait for.

Docs. The partner docs are at docs.sessiontalk.io/docs/partners, covering customer workspaces, partner billing, app logo branding and bringing your own SIP trunk.

If you're comparing partner programmes, our checklist on how to choose a VoIP reseller program covers what to ask each vendor. For bundling voice into your service plans, see our guide to packaging hosted PBX for MSPs and telecom resellers. To see the phone system your customers would use, visit the SessionPBX hosted PBX page. When you're ready, apply to the SessionPBX Partner Programme.

FAQ

What does multi-tenant mean in a PBX?

It means one phone platform runs many separate customer phone systems, called tenants. Each tenant has its own users, extensions, numbers, call flows and admins, and customers can't see each other's setup.

Can each customer have its own SIP trunk?

Yes, on a bring-your-own-trunk platform. With SessionPBX, you connect each customer's trunk from any SIP-compliant carrier by IP or credentials, and the carrier bills for numbers and calls.

Do I have to run my own server?

No. With SessionPBX hosted, SessionTalk hosts and maintains it and there's nothing to install. Self-hosted is an option for approved partners who want to run it on their own server.

Can customers be hosted in different countries?

Yes. On SessionPBX hosted, you choose where each customer is hosted: the UK (London), the US (New York) or Singapore. Each region has its own database.

Is a multi-tenant PBX secure?

It depends on the platform and how you run it. On SessionPBX, SIP signalling, messaging and the admin portal use TLS, and stored SIP trunk credentials are encrypted with AES-256-GCM. Admin roles, strong passwords and careful provisioning matter too; our cloud PBX security checklist covers the basics.

Where can I see partner pricing?

On the SessionPBX Partner Programme page. Partner pricing applies to both hosted and self-hosted.