# sipgate flow

> Real-time voice API for AI phone agents

Give your AI a voice on the phone. Real-time speech, EU-hosted, GDPR-compliant.

## Table of Contents

### Getting Started

- [API Reference](/api.md)
- [Authentication](/api/authentication.md)
- [Quick Start](/api/quick-start.md)

### Protocol

- [HTTP Webhooks](/api/http-webhooks.md)
- [WebSocket Integration](/api/websocket.md)
- [Event Flow](/api/event-flow.md)

### Guides

- [Outbound Calls](/api/guides/outbound-calls.md)
- [Phone Number Routing: Multiple Assistants, One Webhook](/api/guides/phone-number-routing.md)
- [Streaming LLM Responses: Sentence-by-Sentence Best Practices](/api/guides/streaming-llm-responses.md)
- [Barge-In Best Practices: Handling User Interruptions Gracefully](/api/guides/barge-in-best-practices.md)
- [Handling Long-Running Requests in Voice AI: The Async Hold Pattern](/api/guides/async-hold-pattern.md)
- [Testing Voice Assistants Without Making Phone Calls](/api/guides/testing-voice-assistants.md)

### Events

- [Event Types](/api/events.md)
- [Session Start Event](/api/events/session-start.md)
- [User Speech Started Event](/api/events/user-speech-started.md)
- [User Speak Event](/api/events/user-speak.md)
- [Assistant Speak Event](/api/events/assistant-speak.md)
- [Assistant Speech Ended Event](/api/events/assistant-speech-ended.md)
- [DTMF Received Event](/api/events/dtmf-received.md)
- [Session End Event](/api/events/session-end.md)

### Actions

- [Action Types](/api/actions.md)
- [Speak Action](/api/actions/speak.md)
- [Audio Action](/api/actions/audio.md)
- [Mix Audio Action](/api/actions/mix-audio.md)
- [Hangup Action](/api/actions/hangup.md)
- [Transfer Action](/api/actions/transfer.md)
- [Barge-In Action](/api/actions/barge-in.md)
- [Configure Transcription Action](/api/actions/configure-transcription.md)
- [Configure Voice-to-Voice Action](/api/actions/configure-voice-to-voice.md)
- [Send SMS Action](/api/actions/send-sms.md)

### Configuration

- [TTS Providers](/api/tts-providers.md)
- [Barge-In Configuration](/api/barge-in.md)
- [VAD (Voice Activity Detection) Configuration](/api/vad.md)

### Getting Started

- [SDK Guide](/sdk.md)
- [Installation](/sdk/installation.md)
- [Quick Start](/sdk/quick-start.md)

### Core Concepts

- [Core Concepts](/sdk/core-concepts.md)
- [Response Types](/sdk/response-types.md)

### API Reference

- [API Reference](/sdk/api-reference.md)
- [Event Types](/sdk/events.md)
- [Action Types](/sdk/actions.md)
- [TTS Providers](/sdk/tts-providers.md)
- [Barge-In Configuration](/sdk/barge-in.md)
- [VAD (Voice Activity Detection) Configuration](/sdk/vad.md)

### Integration Guides

- [Express.js Integration](/sdk/integrations/express.md)
- [WebSocket Integration](/sdk/integrations/websocket.md)
- [Outbound Calls](/sdk/outbound-calls.md)
- [Examples](/sdk/examples.md)

### Advanced

- [Working Without the Assistant Wrapper](/sdk/advanced/direct-integration.md)
- [Complete Event Reference](/sdk/advanced/events.md)
- [Complete Action Reference](/sdk/advanced/actions.md)
- [Validation with Zod](/sdk/advanced/validation.md)

### Troubleshooting

- [Troubleshooting](/sdk/troubleshooting.md)

### Other

- [Changelog](/changelog.md)
- [Documentation](/README.md)
- [Documentation Setup Guide](/SETUP.md)
- [FAQ — sipgate flow](/faq.md): Frequently asked questions about sipgate flow — the GDPR-compliant, EU-hosted real-time voice and telephony layer that connects phone calls to your own AI agents.
- [User Input Timeout Event](/api/events/user-input-timeout.md)