Asterisk vs Infobip Voice API

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.

Infobip Voice API provides programmable voice tools for mobile and web applications, including calls to landlines and mobile phones. Developers can use Calls API to build inbound and outbound applications and control calls over PSTN, WebRTC, or SIP. Available functions include programmable calls, voice messages, IVR with DTMF collection, click-to-call, number masking, and browser-based WebRTC. SIP trunking connects a PBX or SBC to Infobip, with static and dynamic inbound call-routing rules. Voice can also be used with Infobip Inbox, Customer Profiles, Chatbots, and Journeys, and calling is documented for WhatsApp and Viber. Speech tools support text-to-speech in more than 100 languages and accents, as well as speech capture and transcription. Native SDKs are supported for JavaScript, Android, and iOS. The service has no free plan, but offers a 60-day trial with limits: 15 outgoing calls or voice messages, 15 incoming calls, and 100 WebRTC calls. Trial phone calls require verified mobile numbers and are capped at five minutes. Recording and conferencing are add-ons; conferencing is required for calls with three or more participants.