# Introduction

> Understand Reply's capabilities, workflows, product specifications, and rules — and build prospecting, outbound, inbox, and AI SDR systems on top of it.

_Status: Reviewed — written against Reply's product documentation on 2026-08-03, not yet confirmed against the running product._

**This site explains what Reply can do and exactly how the product behaves.** Reply is a
sales engagement platform: sequences that combine email, LinkedIn, call, SMS, WhatsApp,
task, and Zapier steps; the Reply Data B2B database for finding prospects; a consolidated
inbox with AI-assigned reply categories; MailToaster email warm-up; native CRM
integrations (Salesforce, HubSpot, Pipedrive, Copper); the Findy Chrome extension; and
Jason AI — an AI SDR that builds and runs campaigns. This documentation is written so a
person *or an AI agent* can decide whether Reply fits a task, understand the rules it
will follow, and jump straight to implementation.

> **Status labels.** Every page carries a status. **Reviewed** pages are grounded in
> Reply's product documentation; pages still labeled **Placeholder** are structural
> scaffolding — treat their detailed claims as unverified until the label is removed.

## Follow the journey

- [What can you build?](/start/what-can-you-build) — AI SDRs, prospecting agents, outbound systems
- [Build an AI SDR](/workflows/build-an-ai-sdr) — the flagship workflow, end to end
- [Capabilities](/capabilities) — can Reply do the task you need?
- [When to use Reply](/start/when-to-use-reply) — and when not to

## Go deeper

- [Learn](/learn) — mechanism explainers: deliverability, warm-up, sequence design
- [Specifications](/specifications) — what each product object is
- [Behavior](/behavior) — the deterministic logic Reply applies
- [Playbooks](/playbooks) — situation recipes for common outbound scenarios
- [How-to](/how-to) — configure it in the product
- [Troubleshooting](/troubleshooting) — why did it not work?
- [Reference](/reference) — exact statuses, limits, calculations
- [Agent index](/start/agent-index) — the compact map for machines

## How this site is organized

| Section | Question it answers |
| --- | --- |
| [Start](/start) | What is Reply, and is it relevant to my task? |
| [Learn](/learn) | How does the underlying mechanism work? |
| [Capabilities](/capabilities) | Can Reply do this? |
| [Workflows](/workflows) | How does the complete outcome work? |
| [Playbooks](/playbooks) | What should I do in my situation? |
| [Specifications](/specifications) | What is this product object? |
| [Behavior](/behavior) | What deterministic logic applies? |
| [How-to](/how-to) | How do I configure it? |
| [Troubleshooting](/troubleshooting) | Why did it fail? |
| [Reference](/reference) | What are the exact values? |

## Reading this site as a machine

```bash
curl https://how.reply.io/llms.txt          # curated index
curl https://how.reply.io/index.json        # site map by section
curl https://how.reply.io/start/agent-index.md   # the agent-oriented summary
# append .md to any page URL for its markdown twin
```

## Build with Reply

- REST API: [docs.reply.io](https://docs.reply.io) — the single source of truth for reference detail
- Agent surfaces: [agents.reply.io](https://agents.reply.io) — MCP, CLI, and skills