Node Overview

Every element on the Voiceblox canvas is a node. Nodes are grouped into five categories.

Agent

The Agent node is the central orchestrator. There is exactly one per flow.

Node	Description
`Agent`	Configures the agent’s name, persona (system prompt), and language; connects to all component and tool nodes

Component

Component nodes define the AI capabilities of your agent.

Node	Handle	Description
`LLM`	`llm_in`	Language model for generating responses
`TTS`	`tts_in`	Text-to-speech for voice output
`STT`	`stt_in`	Speech-to-text for voice input
`Avatar`	`avatar_in`	Visual avatar rendering (optional)

Conversation

Conversation nodes form the step chain — the sequence of actions during a call.

Node	Description
`Start`	Entry point. Agent speaks its opening line.
`Burst`	A fixed number of back-and-forth exchanges.
`Open Talk`	Unlimited free-form conversation on a topic.
`Timer`	Conversation capped at a time duration.
`If/Else`	Binary branch based on an LLM-evaluated condition.
`Categorize`	Multi-way branch by semantic classification.
`Transfer`	Hand off to another agent or phone number.
`End`	Terminates the conversation.

Tools

Tool nodes connect to the Agent’s tools_in handle and give the LLM access to external capabilities during a conversation.

Node	Description
`MCP`	Exposes tools from an MCP server to the LLM
`Exa`	Gives the LLM real-time web search via Exa.ai
`SIP Transfer`	Lets the LLM transfer a call to a human phone number

Post-Processing

Post-processing nodes run after the conversation ends. Chain them after an End node.

Node	Description
`Structured Output`	Extracts structured data from the conversation using an LLM
`Webhook`	Fires an HTTP POST with conversation data to an external endpoint

Connection diagram

[LLM] ──llm──▶ [Agent] ◀──tools── [MCP / Exa / SIP Transfer]
[TTS] ──tts──▶    │
[STT] ──stt──▶    ▼
              [Start] ──▶ [Burst] ──▶ [End]
                                        │
                             [Structured Output] ──▶ [Webhook]

Getting Started

Building Flows

AI-Powered Generation

Testing Your Agent

Tools

Post-Processing

Deployment

Node Overview

Node Overview

Agent

Component

Conversation

Tools

Post-Processing

Connection diagram

​Node Overview

​Agent

​Component

​Conversation

​Tools

​Post-Processing

​Connection diagram

Node Overview

Agent

Component

Conversation

Tools

Post-Processing

Connection diagram