Fonoster is presented as an open-source alternative to Twilio, designed to help users engage with their customers using voice or messaging through a single platform. It provides tools and SDKs to build voice applications that can be deployed rapidly.

Here are some of its key features and functionalities:

• Voice Applications: Fonoster supports building voice applications with verbs like Play, Say, and Gather.

• Authentication: It offers project-level authentication using OAuth2 and JWT tokens.

• Storage: Fonoster provides the ability to store, organize, and use sounds from S3 buckets.

• SDKs and Tooling: It provides SDKs and tools for faster application development. These SDKs can be used in browsers or NodeJS applications.

• Command-Line Tool: A command-line tool is available for rapid creation and deployment of applications.

• Google Speech APIs: Fonoster integrates with Google Speech APIs, enabling text-to-speech and automatic speech recognition functionalities.

• Community Support: It is supported by a growing community of contributors and has a Discord community.

• Pricing: Fonoster offers a free, rate-limited plan for learning and prototyping, as well as paid plans suitable for small and medium businesses and for those requiring high levels of security and compliance. The free plan includes 1 workspace, 1 domain, 30 mins/month, 1GB storage, 1-week log retention, and community support.

• Self-Hosting: The open-source version can be self-hosted for free.

• Customer Support: Support options vary based on the pricing plan, ranging from community support for the free plan to email support for Pro plans and technical support with SLAs for Advanced plans.

• API: Fonoster can be used to create calls using an API

• Testimonials: Users have praised it as a cloud-first SIP server and appreciate the community.

Fonoster aims to enable users to create smart voice applications, without unnecessary features or complex customizations.