> ## Documentation Index
> Fetch the complete documentation index at: https://docs.retellai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Testing Overview

> Comprehensive testing methods to validate your AI agent's performance before production deployment

## Introduction

Thorough testing is crucial for building reliable AI phone agents. Retell provides multiple testing methods, each designed to validate different aspects of your agent's behavior and performance.

## Available Testing Methods

### 1. LLM Playground

**Purpose**: Interactive text-based testing for rapid iteration and debugging

**Key Features**:

* Real-time conversation testing
* Function call visualization
* Variable inspection
* Prompt debugging

<Frame>
  <img style={{height: "600px"}} src="https://mintcdn.com/retellai/pRGcctz_zOqy0mSt/images/test-llm/playground.png?fit=max&auto=format&n=pRGcctz_zOqy0mSt&q=85&s=35f434b6b2a91a71d21e8c9f58f7e38e" alt="LLM Playground interface showing conversation testing and function calls" width="888" height="1808" data-path="images/test-llm/playground.png" />
</Frame>

**Best For**: Initial development, prompt refinement, debugging specific conversation paths

### 2. LLM Simulation Testing

**Purpose**: Automated testing with predefined scenarios for consistent quality assurance

**Key Features**:

* Batch testing capabilities
* Success metrics and scoring
* Scenario templates
* Regression testing

<Frame>
  <img style={{height: "600px"}} src="https://mintcdn.com/retellai/pRGcctz_zOqy0mSt/images/simulation.png?fit=max&auto=format&n=pRGcctz_zOqy0mSt&q=85&s=6c68c193e76043fb3433b8332c2ad4ee" alt="Simulation testing dashboard showing test scenarios and success metrics" width="870" height="1760" data-path="images/simulation.png" />
</Frame>

**Best For**: Quality assurance, regression testing, validating changes before deployment

### 3. Web Call/Phone Call Testing

**Purpose**: Real-world testing with actual voice interactions to validate audio performance

**Key Features**:

* Test voice quality and latency
* Validate interruption handling
* Check background noise processing
* Verify DTMF and telephony features

<Frame>
  <img style={{height: "600px"}} src="https://mintcdn.com/retellai/pRGcctz_zOqy0mSt/images/test-llm/test-web-call.png?fit=max&auto=format&n=pRGcctz_zOqy0mSt&q=85&s=d02e4acd0ad95c63137fc0ce9e60f754" alt="Web call testing interface for making test calls to your agent" width="894" height="1800" data-path="images/test-llm/test-web-call.png" />
</Frame>

**Best For**: Final validation, voice quality testing, production readiness checks

## Testing Method Comparison

| Feature               |   LLM Playground  |   LLM Simulation  | Web/Phone Call | Audio Simulation |
| --------------------- | :---------------: | :---------------: | :------------: | :--------------: |
| **Availability**      |     All agents    |     All agents    |   All agents   |    Coming soon   |
| **Setup effort**      |       Medium      |        Low        |      High      |        Low       |
| **Test speed**        |        Fast       |     Very fast     |    Real-time   |       Fast       |
| **Response accuracy** |         ✅         |         ✅         |        ✅       |         ✅        |
| **Function calls**    |         ✅         |         ✅         |        ✅       |         ✅        |
| **Background noise**  |         ❌         |         ❌         |        ✅       |         ✅        |
| **Interruptions**     |         ❌         |         ❌         |        ✅       |         ✅        |
| **Batch testing**     |         ❌         |         ✅         |        ❌       |         ✅        |
| **Cost**              | Price per message | Price per message |  Call charges  |       Free       |

## Recommended Testing Workflow

### Phase 1: Development Testing

**Tool**: LLM Playground

* Iterate on prompts and conversation flows
* Debug function calling logic
* Test edge cases interactively
* Validate dynamic variables

### Phase 2: Quality Assurance

**Tool**: LLM Simulation Testing

* Create comprehensive test scenarios
* Run regression tests after changes
* Validate success metrics
* Ensure consistent performance

### Phase 3: Production Validation

**Tool**: Web/Phone Call Testing

* Test actual voice interactions
* Verify audio quality and latency
* Check telephony features
* Validate real-world performance

### Phase 4: Continuous Testing

**Tool**: Batch Testing (Simulation)

* Set up automated test suites
* Monitor agent performance over time
* Catch regressions early
* Maintain quality standards

<Tip>
  **Pro tip**: Create a test checklist covering all critical paths before each deployment. Include both happy paths and edge cases.
</Tip>