siphon

Siphon is an open-source voice AI framework designed for building production-grade AI calling agents on users' own infrastructure, providing full control over data, costs, and AI providers. It's targeted at enterprises and developers seeking to create scalable telephony applications without platform fees or lock-in. Siphon's key differentiator is its ability to connect users' AI stack to the telephone network, managing state, latency, and interruptions in real-time.

siphon is best for . It sits in the Coding category and is a freemium option.

siphon is listed as freemium. Check the official website for current, detailed pricing tiers.

siphon scored 8.4 out of 10 in 2026, based on six weighted metrics: usefulness, quality, ease of use, value, reliability, and popularity.

Siphon offers a robust and scalable framework for building reliable telephony applications, with features like automatic load balancing, limitless workers, and real-time latency. It provides full control over data, costs, and AI providers, allowing users to choose their own infrastructure and AI/telephony providers, such as OpenAI and Twilio. Siphon is 100% open-source under the Apache 2.0 license, with zero platform fees, making it an attractive option for enterprises seeking to reduce costs.

Siphon requires users to have their own infrastructure and AI/telephony providers, which can be a barrier to entry for smaller organizations or those without existing infrastructure. The framework may require significant development and integration efforts to get started, which can be time-consuming and resource-intensive. Siphon's open-source nature means that users are responsible for their own support and maintenance, which can be a challenge for those without extensive technical expertise.

siphon is a solid, well-rounded option for . Its 8.4/10 score reflects dependable performance in the Coding category.