Synthflow

Synthflow AI is a web-based AI voice agent platform for businesses that want to automate inbound and outbound phone calls without coding.

Key capabilities include:

• No-code flow designer to build call logic for use cases like customer service, receptionist, lead qualification, appointment setting, and IVR
• Speech-to-text, LLM, and text-to-speech voice conversations, including GPT-4 and GPT-5 options and ElevenLabs voices
• Actions during calls such as real-time booking, warm transfer to a human, voicemail detection, and SMS follow-ups
• Operations and integrations including call recording and transcription, CRM connections, and an API for custom actions and workflow automation

Pricing: Free to start, then pay-as-you-go usage-based billing (voice, LLM, and telephony minutes). Enterprise pricing is available for 10,000+ minutes/month; add-ons and extra concurrency are priced separately.

Notable for its end-to-end approach that combines agent building, testing, and deployment with in-house telephony, plus compliance and security claims including SOC 2, HIPAA, GDPR, and ISO 27001 support for regulated use cases.