Overview
Flow Builder includes a built-in test panel on the right side of the canvas where you simulate conversations before deploying to production. It connects directly to your flow’s engine using your configured API key.Starting a Test
Ensure API Key is Configured
Click Test
The test drawer opens on the right. The start node fires automatically and you see the agent’s opening message.
Key Features
Reset Session
Click Reset to clear the conversation, reset all variables, and return to the start node. Reset frequently — stale variable values can mask bugs.Conversation History
The test drawer shows:- Agent messages — Responses from Conversation nodes
- User messages — Your test inputs
- System events — Node transitions, variable changes, API call results
Variable Inspector
Inspect the current state of all flow variables at any point. Use this to verify Extraction nodes capture data correctly.Voice Testing
If configured for voice deployment, test how the agent sounds with TTS, validate interruption handling, and confirm speak-during-execution filler works during tool calls.Tips for Effective Testing
- Test edge cases — Unexpected inputs, empty responses, off-topic messages
- Watch the canvas — The highlighted node path shows routing correctness
- Check variables after extraction — Use the variable inspector to confirm accuracy
- Test every branch — Walk through all Logic node paths
- Reset between scenarios — Don’t rely on stale variable state
Related Pages
API Key Setup
Configure your LLM API key
Conversation Node
The core dialogue node
Engine & Streaming
How the engine processes turns
Voice Connection
Deploy to voice via Telnyx