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Asterisk

asterisk.org

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Spec score 8.0 #9 of 52 in Voice APIs

What it is

Asterisk is a free, open-source framework for building communications applications and turning an ordinary computer into a communications server. It powers IP PBX systems, VoIP gateways, conference servers, call centers, voicemail servers, and IVR systems. Listed functions include call routing, recording, queuing, conferencing, voicemail, automated attendants, and call transfers. Computer-telephony interfaces include AGI, AMI, and the Asterisk REST Interface (ARI); listed VoIP protocols include SIP, H.323, IAX, Jingle/XMPP, MGCP, and SCCP. Asterisk can connect communications to applications, including CRM systems through AMI. The source code can be downloaded, and the project points users to installation on a modern cloud Linux instance. Building applications requires working knowledge of Linux, scripting, networking, and telephony. Asterisk is distributed under GPLv2; Sangoma offers commercial licensing for uses incompatible with that license. The Asterisk forum provides community help with installation, upgrades, and operation.

Spec sheet

Purpose
Asterisk is an open source framework for building communications applications and turns an ordinary computer into a communications server.Read 4 Oct 2026 · asterisk.org
Deployment
Asterisk can be downloaded as source code, and the site points users to install it on a modern cloud Linux instance.Read 4 Oct 2026 · asterisk.org
Integrations
The site says Asterisk can connect communications to applications, including Salesforce automation or CRM systems using AMI.Read 4 Oct 2026 · asterisk.org
Support
Sangoma offers five support levels for core components of current open source Asterisk versions, with Level 5 reserved for customers requiring an SLA and engineering support.Read 4 Oct 2026 · asterisk.org
Founded
1999Read 28 Sep 2026 · asterisk.org
Community help
The Asterisk forum offers community help and feedback on installation, upgrading and running Asterisk.Read 4 Oct 2026 · asterisk.org
Features
Its listed features include call routing, recording, queuing, conferencing, voicemail, IVR, automated attendants and call transfers.Read 4 Oct 2026 · asterisk.org
Interfaces
Computer-telephony interfaces include AGI, AMI and the Asterisk REST Interface (ARI).Read 4 Oct 2026 · asterisk.org
Licensing
Asterisk is distributed under GPLv2 and Sangoma offers commercial licensing for uses that are incompatible with GPLv2.Read 4 Oct 2026 · asterisk.org
Linux requirement
The site says building applications with Asterisk requires working knowledge of Linux, scripting, networking and telephony.Read 4 Oct 2026 · asterisk.org
Notable limitation
MFC-R2 is listed as not supported, although the page says a patch is available.Read 4 Oct 2026 · asterisk.org
Protocols
Listed VoIP protocols include SIP, H.323, IAX, Jingle/XMPP, MGCP and SCCP.Read 4 Oct 2026 · asterisk.org
Sponsor
Asterisk is sponsored by Sangoma.Read 4 Oct 2026 · asterisk.org
Use cases
Asterisk powers IP PBX systems, VoIP gateways, conference servers, call centers, voicemail servers and IVR systems.Read 4 Oct 2026 · asterisk.org

Plans and prices

Asterisk Free Free and open source · GPLv2 · download free of charge Read 4 Oct 2026 · asterisk.org

Every Asterisk plan and price →

Strong points and limits

Strong points

  • Free and open source under GPLv2
  • Supports SIP, H.323, and other listed protocols
  • Includes call routing, recording, and conferencing
  • Offers AGI, AMI, and ARI interfaces
  • Community forum covers installation and upgrades

Limits

  • Building applications requires Linux and telephony knowledge
  • MFC-R2 is not supported, though a patch is available
  • Commercial licensing may be needed for incompatible uses

Who it suits

It suits teams building communications systems that can work with Linux, scripting, networking, and telephony. The GPLv2 license and commercial licensing option may matter to prospective users.

Verdict

Asterisk provides a broad framework for communications applications, with multiple interfaces and protocols. Its technical requirements and licensing terms are important considerations before building on it.

Where Specifiction places it

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