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T12 · T12-R34 · Open alternatives

FreeSWITCH and Asterisk

FreeSWITCH and Asterisk are open alternatives to buying a hosted voice API. They are not drop-in copies of Twilio's TwiML. FreeSWITCH's manual is a configuration book. Asterisk's dialplan is extensions.conf. A CPaaS webhook is a third control style.

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Counts on this page

4boxes
5opened sources
2confirm rows
5study lines

Opened sources

Confirm rows, no URL

Learn it in 5 minutes

  • Wikipedia says FreeSWITCH is free and open-source telephony software for audio, video, and text, with SIP features, and that it runs on Linux, Windows, macOS, and FreeBSD.
  • The article says the latest release is version 1.10, and that SignalWire was founded in 2018 to provide commercial services on an elastic FreeSWITCH core.
  • The FreeSWITCH manual that opened says it covers XML configuration, the user directory, SIP profiles, the dialplan, codecs, WebRTC, and integration interfaces.
  • Asterisk is the software PBX already cited, and its docs navigation lists Asterisk 18 through 24.
  • Asterisk's article says users extend it with dialplan, modules, or AGI programs.

Visual

FreeSWITCH and Asterisk Open. Teaching sketch. Confirm a live system. FreeSWITCH 1.10 Asterisk Dialplan Names come from pages opened in 2026-10. A missing name stays confirm.

Count the boxes: 4. Each label is a name from a page or a study label marked on the drawing.

Flow

FreeSWITCH and Asterisk Caller SIP Called session setup session setup RTP, not required to hairpin Teaching sketch from RFC 3261 and RFC 3550. Not a packet capture.

What is going on

FreeSWITCH and Asterisk are open alternatives to buying a hosted voice API. They are not drop-in copies of Twilio's TwiML. FreeSWITCH's manual is a configuration book. Asterisk's dialplan is extensions.conf. A CPaaS webhook is a third control style.

Version 1.10 is the Wikipedia article's latest-release sentence, read in October 2026. If you install software, confirm the current tarball yourself. The article can lag. The docs navigation's version list is what the Asterisk site showed, not a ranking.

Worked example

Two control planes. Asterisk: extensions.conf and dialplan reload, from the docs. FreeSWITCH: SIP profiles and dialplan, from the manual's table of contents. A webhook IVR stays in the TwiML room.

Quiz

1. The FreeSWITCH article says version 1.10 is the latest release.

2. FreeSWITCH's manual is a Twilio TwiML reference.

Ecosystem

Sister pieces sit on the ecosystem page: the glossary, the mind map, the integration map, and the bridges.

  • SIP profile — A FreeSWITCH configuration topic the manual's introduction says it covers.
  • AGI — Asterisk Gateway Interface. The article says AGI programs can use standard streams or TCP sockets.

Config. Write the software name and the file or profile you changed. One change, then put it back if the symptom does not move.

Troubleshooting. If WebRTC fails on FreeSWITCH, the manual says WebRTC is in scope. That does not mean the default profile has it. Read the profile you are running.

Bridge. SignalWire is the company the article says sponsors FreeSWITCH and sells a cloud service. It is not Twilio. A SignalWire price was not opened.

Mind map, sister technologies, and future hooks live on the ecosystem page.

Sources and go deeper

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

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