Five9

Best Self Hosted Alternatives to Five9

A curated collection of the 3 best self hosted alternatives to Five9.

Cloud contact-center (CCaaS) platform for inbound/outbound voice, IVR, omnichannel digital channels, predictive/outbound dialing, workforce management and analytics; integrates with CRMs and provides APIs for routing and reporting.

Alternatives List

#1
Asterisk

Asterisk

Open-source PBX and telephony toolkit for building communications applications; modular C-based engine with SIP, WebRTC, RTP, ARI/AMI APIs and hardware support.

Asterisk screenshot

Asterisk is an open-source telephony engine and PBX toolkit implemented primarily in C and developed for GNU/Linux. It exposes traditional PBX features and low-level telephony primitives so developers and operators can build SIP, WebRTC and PSTN-connected communications applications.

Key Features

  • Modular, channel-based architecture with pluggable modules for SIP (chan_pjsip / chan_sip), media, codecs and hardware interfaces
  • WebRTC support (WSS/DTLS-SRTP), RTP/RTCP handling, and modern codec support including Opus for browser and realtime audio
  • ARI (Asterisk REST Interface) exposing REST + WebSocket events for building custom programmable call applications
  • AMI and AGI interfaces for management, automation and traditional dialplan scripting; full CLI and menuselect build configuration
  • PSTN and telephony hardware integration (traditional telephony cards and drivers) alongside VoIP gateway capability
  • Source-driven build system using autoconf/Autotools and GNU Make; extensive documentation, community forum and release advisories

Use Cases

  • Deploying an enterprise or branch PBX providing calls, voicemail, conferencing, queues and call routing
  • Acting as a VoIP gateway or SBC to bridge SIP/WebRTC clients with PSTN trunks and telephony hardware
  • Building programmable communications services (IVR, voicebots, conferencing, call recording) using ARI or AMI

Limitations and Considerations

  • Nontrivial operational complexity: requires careful configuration, dependency management and familiarity with telephony concepts
  • Requires proactive security and performance tuning (file-descriptor limits, TLS/DTLS configuration); security advisories are periodically published for critical fixes
  • Feature surface is large and modularity means some functionality requires enabling/building specific modules or external libraries

Asterisk is a mature, widely adopted telephony engine suited for operators and developers who need deep control over call handling and media. It is maintained by a large community and is intended for production PBX and programmable-telephony deployments.

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#2
Wazo Platform

Wazo Platform

Open-source, API-first platform for carrier-grade IP communications: VoIP, WebRTC, messaging, conferencing and programmable telephony microservices.

Wazo Platform screenshot

Wazo Platform is an open-source, API-first project for building carrier-grade IP communication infrastructures. It provides microservices, APIs and SDKs to deliver VoIP, WebRTC, messaging, conferencing, call center and PBX features for custom and scalable deployments. (wazo-platform.org)

Key Features

  • API-first microservices implemented primarily in Python, exposing REST APIs, WebSockets and Webhooks. (github.com)
  • Call-control and telephony services (wazo-calld) for creating and managing calls, voicemail, transfers and switchboards. (github.com)
  • WebRTC-enabled softphone SDKs and demos for embedding browser-based voice/video clients. (github.com)
  • Engine integration with telecom components (Asterisk, Kamailio, RTPEngine) and a technical stack using Nginx, RabbitMQ and PostgreSQL. (wazo-platform.org)
  • Container and packaging support (Docker / docker-compose) and OpenAPI-described endpoints for easier integration. (github.com)

Use Cases

  • Build a white-label UCaaS or MSP offering with programmable VoIP, chat and conferencing.
  • Integrate an embedded softphone or add telephony features into web and mobile apps.
  • Deploy SIP routing, session border controller or contact center/call-center services.

Limitations and Considerations

  • Wazo relies on third-party telecom components (Asterisk, Kamailio, RTPEngine); deploying and operating production telecom stacks requires telephony and infrastructure expertise. (wazo-platform.org)
  • The community maintains most components and some container tooling is marked experimental; CI/packaging and deployment workflows may need adaptation for production. (github.com)

Wazo Platform provides a modular, extensible foundation for building programmable telephony and UC solutions. It targets operators, MSPs and developers who need deep customization and API-level control over telecommunication features. (wazo-platform.org)

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#3
FreePBX

FreePBX

Modular, PHP/JavaScript web GUI that configures and manages Asterisk PBX features, endpoints, and call routing for businesses and service providers.

FreePBX screenshot

FreePBX is an open-source, web-based graphical user interface designed to configure and manage Asterisk telephony servers. It provides a modular platform of built-in features and extensible modules to build IP PBX, UC, and call-centre systems.

Key Features

  • Web-based administrative GUI for configuring Asterisk dialplans, trunks, extensions, IVRs, queues, voicemail and CDR reporting
  • Modular architecture with many open-source modules and an add-on marketplace for commercial extensions (provisioning, call center features, CRM integration)
  • User Control Panel (UCP) for end-user voicemail, call handling, web softphone and customizable widgets
  • Zero-touch phone provisioning and endpoint management for supported IP phones
  • SIP trunking and provisioning integrations, session border controller (SBC) support, and tools for analog/PRI gateway integration
  • REST/API hooks and token-based access for automation and third-party integration
  • Built for common Linux stacks with emphasis on PHP/JavaScript modules and standard LAMP-style components

Use Cases

  • Small-to-medium businesses deploying a full-featured IP PBX with IVR, voicemail, and ring groups
  • Contact centers and help desks using queueing, CDR reporting, and commercial call-center modules
  • Integrators and service providers packaging custom modules, provisioning endpoints, and managing SIP trunking for customers

Limitations and Considerations

  • Core FreePBX is open source but many advanced or enterprise modules are commercial and sold through the add-on marketplace
  • Relies on Asterisk as the telephony engine; feature set and behavior depend on Asterisk versions and underlying Linux distribution

FreePBX is a mature, widely used platform for building customizable telephony systems. Its modular design and large ecosystem make it suitable for many business telecom deployments, while advanced features may require paid modules or vendor support.

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Why choose an open source alternative?

  • •Data ownership: Keep your data on your own servers
  • •No vendor lock-in: Freedom to switch or modify at any time
  • •Cost savings: Reduce or eliminate subscription fees
  • •Transparency: Audit the code and know exactly what's running