Asterisk
Asterisk is a free, open-source framework for building communications applications.
What Asterisk is
Asterisk is a free, open-source framework for building communications applications. It can turn an ordinary computer into a communications server and powers systems such as IP PBX, VoIP gateways, conference servers, call centers, voicemail and IVR. Listed functions include routing, recording, queuing, conferencing, voicemail, automated attendants and call transfers. It offers computer-telephony interfaces including AGI, AMI and ARI, and supports protocols such as SIP, H.323, IAX, Jingle/XMPP, MGCP and SCCP. Asterisk can connect communications to applications, including CRM systems through AMI. Its source code can be downloaded, and the project points users to installation on a modern cloud Linux instance. Building applications with Asterisk requires working knowledge of Linux, scripting, networking and telephony. It is distributed under GPLv2; Sangoma offers commercial licensing for uses incompatible with that license. Community help is available through the Asterisk forum.
Good
- Free and open source under GPLv2
- Supports call routing, recording and conferencing
- Includes SIP and other VoIP protocols
- Offers AGI, AMI and ARI interfaces
Watch out
- Building applications requires Linux and telephony knowledge
- MFC-R2 is not supported, though a patch is available
- Commercial licensing may be needed for GPL-incompatible uses
Who it suits
Asterisk suits people building communications systems who are comfortable with Linux, scripting, networking and telephony. It may also fit organizations that need to connect telephony with applications such as CRM systems.
Verdict
Asterisk provides a broad set of communications building blocks at no charge under GPLv2. Its technical requirements make it a better fit for users equipped to work with Linux, networking and telephony.
Plans and prices
From Asterisk's own pricing page, checked 4 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Asterisk | Free | Free and open source · GPLv2 · download free of charge |
The facts
Each one read from Asterisk's own pages, with the date it was checked.
What it does
- Community help
- The Asterisk forum offers community help and feedback on installation, upgrading and running Asterisk.checked 4 Oct 2026
- Deployment
- Asterisk can be downloaded as source code, and the site points users to install it on a modern cloud Linux instance.checked 4 Oct 2026
- Features
- Its listed features include call routing, recording, queuing, conferencing, voicemail, IVR, automated attendants and call transfers.checked 4 Oct 2026
- Integrations
- The site says Asterisk can connect communications to applications, including Salesforce automation or CRM systems using AMI.checked 4 Oct 2026
- Interfaces
- Computer-telephony interfaces include AGI, AMI and the Asterisk REST Interface (ARI).checked 4 Oct 2026
- Licensing
- Asterisk is distributed under GPLv2 and Sangoma offers commercial licensing for uses that are incompatible with GPLv2.checked 4 Oct 2026
- Notable limitation
- MFC-R2 is listed as not supported, although the page says a patch is available.checked 4 Oct 2026
- Protocols
- Listed VoIP protocols include SIP, H.323, IAX, Jingle/XMPP, MGCP and SCCP.checked 4 Oct 2026
- Purpose
- Asterisk is an open source framework for building communications applications and turns an ordinary computer into a communications server.checked 4 Oct 2026
- Sponsor
- Asterisk is sponsored by Sangoma.checked 4 Oct 2026
- 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.checked 4 Oct 2026
- Use cases
- Asterisk powers IP PBX systems, VoIP gateways, conference servers, call centers, voicemail servers and IVR systems.checked 4 Oct 2026
The company
- Founded
- 1999checked 28 Sep 2026
Where it runs
- Linux requirement
- The site says building applications with Asterisk requires working knowledge of Linux, scripting, networking and telephony.checked 4 Oct 2026
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