app · Retell AI
Retell AI
Retell AI doesn't try to be the model — it's the orchestration layer that wires your chosen speech-to-text, LLM, and text-to-speech providers together into a phone-ready voice agent, handling call routing, telephony (SIP/Twilio), conversation state, and interruption logic for you. You bring your own API keys for each component, so you keep full control and full visibility over exactly what each piece costs and how it behaves — nothing is hidden inside a black box. This transparency is why it's become popular specifically for phone-based agents (appointment booking, support lines, outbound calling), where reliability and auditability matter more than squeezing out the last few milliseconds. Vapi is a close competitor with a similar bring-your-own-stack philosophy, if you want to compare. Retell is the right choice when you want to control your stack precisely and need real telephone integration, not just a browser demo.
What it can help with
- voice agent
- telephony integration
- bring-your-own-api
- call routing
- speech-to-text
- text-to-speech
- conversation state
- outbound calling