# Lesson 3: Platform Overview: Build → Test → Deploy → Monitor

**URL:** https://community.retellai.com/t/lesson-3-platform-overview-build-test-deploy-monitor/2921
**Category:** Module 1: What Is Retell?
**Created:** [May 31, 2026, 1:52am UTC](https://community.retellai.com/t/lesson-3-platform-overview-build-test-deploy-monitor/2921 "2026-05-31T01:52:21Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![system](https://canada1.discourse-cdn.com/flex008/uploads/retell1/original/2X/a/a06e2942efdc48016940732a05d1274957507ee3.png) [@system](https://community.retellai.com/u/system)
#### Post date: [May 31, 2026, 1:52am UTC](https://community.retellai.com/t/lesson-3-platform-overview-build-test-deploy-monitor/2921/1 "2026-05-31T01:52:21Z")

</div>

## Platform Overview

Retell is organized around four stages:

### 🔨 Build

- **Agent creation** — define personality, instructions, and behavior via prompts
- **Conversation Flows** — visual node-based editor for complex multi-step calls
- **Knowledge Base** — upload docs, URLs, or text for the agent to reference
- **Custom Functions** — call external APIs during conversations (check availability, look up records, etc.)

### 🧪 Test

- **Playground** — web-based environment to have test conversations with your agent
- **Simulation Testing** — run automated test scenarios at scale to validate behavior

### 🚀 Deploy

- **Phone Numbers** — buy numbers directly or bring your own (Twilio, Vonage, custom SIP)
- **Inbound/Outbound** — handle incoming calls or make outgoing calls via API
- **Batch Calls** — launch campaigns of outbound calls
- **Web/Chat** — embed agents in websites as voice or text chat

### 🔍 Monitor

- **Call Logs** — full transcripts, recordings, and metadata for every call
- **Post-Call Analysis** — extract structured data from calls (sentiment, outcomes, custom fields)
- **Webhooks** — get real-time notifications for call events
- **AI QA** — automated quality scoring across call cohorts