Asterisk Review, Pricing & Features

Asterisk is a free, open-source toolkit for building PBX, VoIP, and telephony applications, maintained by Sangoma since its 1999 launch.

Category: Communication
Pricing: Free (open source), from Free
Verified: Not yet
Last updated: July 18, 2026
Founded: 1999

APIOpen SourceSelf-Hosted

Overview

Asterisk is an open-source framework for building PBX systems, VoIP gateways, and other telephony applications. Created in 1999 by Mark Spencer, it is now maintained by Sangoma Technologies, which also develops the FreePBX graphical interface commonly paired with it.

Running on standard server hardware, Asterisk handles call routing, IVR, voicemail, conferencing, and interconnection between the PSTN and VoIP networks.

Key Features

Asterisk supports core PBX functionality, wide VoIP protocol coverage (including SIP and IAX2), IVR and call routing, conferencing, and voicemail/call recording.

It is extensible through a dialplan scripting language and APIs (AGI, AMI, ARI), letting developers integrate it with custom applications, call centers, and third-party systems.

Who It's For

Asterisk suits IT and telecom teams building custom PBX deployments, as well as VoIP service providers and developers building commercial calling platforms, provided they have the Linux and telephony expertise to configure and maintain a self-hosted system.

Key Features

PBX Core Engine — Turns a server into a full-featured private branch exchange.
VoIP Protocol Support — Supports SIP, IAX2, and other protocols for interconnecting VoIP and PSTN endpoints.
IVR & Call Routing — Configurable interactive voice response and call-routing logic via the dialplan.
Conferencing — Built-in audio conferencing capabilities.
Voicemail & Call Recording — Native voicemail boxes and call recording.
Extensible APIs — AGI, AMI, and ARI interfaces let developers integrate custom applications.

Pros & Cons

Pros

Free and fully open source with no licensing fees
Highly extensible and customizable for bespoke telephony needs
Large, long-running community and ecosystem (25+ years)
Works with a wide range of SIP trunking providers and telephony hardware

Cons

Requires Linux and telephony expertise to install, configure, and secure
No built-in graphical interface (commonly requires FreePBX or similar)
Self-hosting means the operator owns all maintenance and security responsibility

Frequently Asked Questions

Is Asterisk free to use?

Yes, Asterisk is free and open source with no licensing cost.

Who maintains Asterisk?

Asterisk was created by Mark Spencer of Digium in 1999 and is now maintained by Sangoma Technologies.

Does Asterisk include a graphical interface?

No, Asterisk is configured via its dialplan and config files by default; most users pair it with FreePBX for a web-based GUI.

What protocols does Asterisk support?

Asterisk supports SIP, IAX2, and other VoIP and traditional telephony protocols.

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