For an open source alternative to Twilio, the strongest matches are ndolestudio/httpsms (This platform provides a programmable SMS API and webhook), fonoster/fonoster (Fonoster is a self-hostable, programmable communications platform that provides) and novuhq/novu (Novu is a notification infrastructure platform that provides a). evolutionapi/evolution-api and signalwire/freeswitch round out the shortlist. Each is ranked by relevance to your query, popularity and recent activity.
Find the best open-source alternatives to Twilio for SMS, voice, and messaging. Compare top-rated programmable APIs to find the right fit for you.
httpsms is a programmable messaging platform that transforms Android hardware into a functional SMS gateway. By bridging mobile devices with web-based services, it enables bidirectional communication through a programmable interface that allows external software to send and receive text messages via HTTP requests. The platform distinguishes itself by providing a secure, automated infrastructure for managing high-volume messaging. It utilizes end-to-end payload encryption to protect sensitive data during transit and incorporates a rate-limited execution engine to regulate transmission frequenc
This platform provides a programmable SMS API and webhook support by turning Android devices into a gateway, making it a specialized tool for SMS-based communication services.
Fonoster is a conversational AI framework and multi-tenant communications platform as a service. It serves as a programmable voice gateway and SIP telephony platform, enabling the creation of voice-based assistants and automated communication workflows using large language models. The project distinguishes itself through a vendor-agnostic speech integration engine that abstracts speech-to-text and text-to-speech providers. It features a multi-tenant architecture that isolates telephony resources and user identities into distinct organizational workspaces. The system covers a broad range of t
Fonoster is a self-hostable, programmable communications platform that provides the core voice and telephony APIs required for building automated workflows and conversational assistants.
This project is a centralized notification infrastructure platform designed to manage multi-channel messaging workflows, delivery routing, and user preference settings through a unified integration layer. It provides a code-first workflow engine that allows engineers to define complex messaging sequences and notification logic as version-controlled code, ensuring consistency across development and deployment pipelines. The platform distinguishes itself by decoupling notification content from application logic, enabling non-technical teams to design and update templates through a visual interf
Novu is a notification infrastructure platform that provides a unified API for multi-channel messaging, including SMS, though it functions as a workflow orchestrator for notifications rather than a direct telephony or voice provider.
Evolution API is a collection of system components including a WhatsApp API gateway, a multi-channel messaging bridge, and a conversational AI orchestrator. It functions as an event-driven messaging middleware that links messaging platforms with large language models and external applications to automate text and audio responses. The project provides a self-hosted marketing automation platform for executing customer relationship workflows and outreach campaigns. It further distinguishes itself by routing chat conversations between different messaging services and customer support tools throug
This is a self-hostable messaging middleware that provides programmable APIs for WhatsApp and multi-channel communication, though it focuses on messaging automation rather than traditional telephony or SMS services.
FreeSWITCH is an open-source software telephony switch that routes and processes voice, video, and messaging calls over IP networks using standard protocols such as SIP and RTP. It serves as both a call routing and switching engine and a programmable telephony API, enabling developers to build custom telephony applications with event-driven call control and media manipulation. As a SIP media server, it handles media streaming, transcoding, and conferencing, and functions as a unified communications platform integrating voice, video, messaging, and conferencing into a single switchable infrastr
FreeSWITCH is a powerful, self-hostable telephony engine that provides the programmable APIs and event-driven architecture required to build custom voice and messaging services, though it functions more as a low-level infrastructure switch than a high-level multi-channel messaging platform.