vs Issabel — open-source PBX without a predictive dialer

VICIdial vs Issabel: which should you pick?

Pick Issabel if you want a free, self-hosted unified-communications platform — PBX, IVR, fax, video — and you have someone to run it. Pick managed VICIdial on VICIfast if the job is outbound: Issabel's own Contact Center manual states it has no predictive dialer, only manual, preview and progressive modes.

Issabel and VICIdial both come out of the Asterisk world and both are free to download, so they land in the same searches. They are not the same kind of software. Issabel describes itself as "free and open source software that allows you to build communication tools for businesses" — a unified communications platform, which is to say a PBX with extras. VICIdial is an outbound dialer.

If you are evaluating the two for an outbound floor, there is one fact that settles most of it, and it comes from Issabel's own documentation. We will get to it below.

Quick summary

What is Issabel, and where did it come from?

Issabel was born in 2017 as a fork of Elastix, created after 3CX acquired Elastix and discontinued the open-source versions. It is the surviving open-source line of that family, licensed under GPLv2 and GPLv3, and the core platform has no licensing cost. It bundles a lot into one ISO — telephony, email, fax, video conferencing, security modules and a REST API.

Two things worth knowing about its current state:

• The last major release is Issabel 5, from April 2024, built on Rocky Linux 8.8 with Asterisk 16 or 18. Development has not stopped — their GitHub repositories show commits through 2026 — but there has not been a new major ISO in a while.
• In October 2025 Issabel stopped selling on-premise servers and hardware and moved to a cloud-first model, honouring existing agreements and maintenance contracts. This applies to hardware and appliances they sold, not to the free ISO, which is still downloadable. But it tells you where the project's commercial attention is going.

Does Issabel have a predictive dialer?

No. This is the clearest fact in the comparison and it comes straight from Issabel's own Contact Center manual, which states: "It's important to note that the Issabel Contact Center does not include a predictive dialer." The modes it implements are manual, preview and progressive.

That matters more than it might sound. Progressive dialing places one call per available agent. Predictive dialing places more than one, using a pacing algorithm that predicts when agents will free up, and it is the reason a predictive floor gets substantially more talk time per agent hour than a progressive one. If your economics depend on agent utilisation, that gap is the whole business case.

You will find blog posts on Issabel's own marketing site discussing predictive dialing, and a Wikipedia line suggesting modules can be added. The technical manual is the authoritative source, and it says what it says. If you are relying on a bolt-on module for predictive behaviour, ask hard questions about who maintains it.

VICIdial's predictive pacing is the core of the product — dial level, drop-SLA enforcement, recycle rules and answering-machine detection are per-campaign settings, on every plan.

What does Issabel cost?

The core platform is free under GPL. The Contact Center is a separately licensed commercial add-on, priced per agent, and those prices are not published — you go through their store or sales. Issabel Cloud does not publish pricing either; the only public figure we could find is a $5 per-user additional PBX fee on one cloud licence page.

So the honest framing is: the PBX is free, the call-centre functionality is not, and you will need a quote to know what it costs. Check their current pricing directly rather than trusting any number in a comparison article.

VICIfast publishes the whole grid. The VICIdial software is free and open source; what you pay for is the managed server, starting at $49/month for Launch and $139/month for Growth in the US. See VICIfast pricing.

What is the real cost of self-hosting either one?

If you are comparing "free Issabel" against "paid VICIfast", compare the whole cost. A self-hosted box means you own the OS patching, the Asterisk upgrades, the CVE response, the firewall, the TLS certificates, the daily backups and the 3am pager when dialing stops. That is a part-time sysadmin role, and it is the single most underestimated line in a self-hosting budget — we wrote it up in the hidden cost of self-hosted VICIdial.

None of that is an argument against self-hosting. It is an argument for pricing it honestly. If you have a sysadmin who already runs Asterisk boxes and enjoys it, self-hosting is a perfectly rational choice.

When is Issabel the better choice?

• You need a PBX, not a dialer. Extensions, voicemail, IVR, conference rooms, fax, internal calling. That is Issabel's job and it does it well for free.
• Outbound is manual or preview. If agents hand-pick every call, you do not need predictive pacing and the free platform is genuinely enough.
• Budget is zero and you have the skills. A GPL stack you can install yourself, with no vendor and no invoice, is a real option that managed hosting cannot match on price.
• You are already in the Elastix world and your team knows the interface.

When is managed VICIdial the better choice?

• You need predictive dialing. Issabel's documentation says it does not have it. That is usually the end of the evaluation for an outbound floor.
• You do not want to be the sysadmin. Patching, backups, firewall, certificates and monitoring are ours. The server is provisioned in about 40 seconds and stays maintained.
• Compliance tooling matters. Per-trunk TCPA scrubbing with your own Blacklist Alliance key, set per outbound carrier — see /features/tcpa-compliance.
• You want a current platform. Actively maintained builds rather than a 2024 ISO.
• You still want root. You get it — full SSH on your own box, with every session recorded as a replayable asciinema cast for audit.

How do you move from Issabel to VICIdial?

Both run Asterisk, so trunk configuration and dial-plan logic translate with some rewriting rather than starting from scratch. If you were running VICIdial on top of Issabel, the schemas overlap directly and a dump restores cleanly. If you were running pure Issabel, your lead data most likely lives in a CRM rather than the PBX, and it loads into vicidial_list as CSV.

The decision to make first is full replacement versus hybrid: keep Issabel for PBX duties and run VICIdial for outbound only, with different DIDs routing to each. Plenty of teams do exactly that.

Full detail is in migrating from Elastix or Issabel to managed VICIdial, and there is background at VICIdial vs Issabel. Contact us to scope it — migration help is free.

Next steps

• Migrating from Elastix or Issabel — the runbook: inventory, full replace versus hybrid, export and cutover.
• VICIfast pricing — the published plan grid, billed per server.
• Managed VICIdial hosting — what runs on the box and who keeps it patched.

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