Why Nixflex
Sub-second response
First audio in ~500ms. speech engine for STT, the AI for reasoning, the voice engine for voice.
Bring your own Twilio
Multi-tenant from day one. Each customer connects their own Twilio account — you keep full control of phone numbers and billing.
Tag-based actions
The agent triggers transfers, SMS, and call endings through prompt tags. No webhook orchestration needed for built-in actions.
History-aware calls
Outbound calls automatically pull past call summaries for the recipient and inject them into the agent’s prompt. Your agent remembers customers across calls.
Get started
Quickstart
Make your first call in under five minutes.
Authentication
Generate API keys and authenticate requests.
Create an agent
Configure prompts, voice, language, and actions.
API reference
Every endpoint with parameters, examples, and error codes.
How it works
A call moves through the engine like this:- Caller dials your Twilio number (or you trigger an outbound call via API).
- Twilio streams audio to Nixflex over WebSocket.
- Speech-to-text converts what the caller says into text in real time.
- The agent reasons over the conversation and decides what to say or do next.
- Text-to-speech turns the reply into natural voice and streams it back to the caller.
- After the call ends, Nixflex runs post-call analysis (summary, sentiment, custom data extraction) and fires your webhook.