# Customer.io Documentation

> Customer.io is a messaging automation platform for sending targeted email, transactional email, push notifications, SMS, in-app messages, and webhooks based on customer behavior and data attributes. These docs cover setup, integration, messaging, segmentation, analytics, API reference, and agent-native access through the Customer.io CLI or MCP server.

Customer.io documentation is organized into the following sections. Each section has its own `llms.txt` file with detailed page listings.

## Sections
- [Get Started](https://docs.customer.io/get-started/llms.txt): Get Started documentation
- [Journeys](https://docs.customer.io/journeys/llms.txt): Journeys documentation
- [Integrations](https://docs.customer.io/integrations/llms.txt): Integrations documentation
- [Account & Workspaces](https://docs.customer.io/accounts-and-workspaces/llms.txt): Manage your account, workspaces, billing, Builder plan, team settings, permissions, and privacy controls.
- [AI](https://docs.customer.io/ai/llms.txt): Use Customer.io with AI tools, including the in-app agent, CLI, MCP server, LLM actions, and docs for agent setup.

## Additional resources

- [Builder plan](https://docs.customer.io/accounts-and-workspaces/billing/builder-plan.md): Pay-as-you-go messaging infrastructure for early-stage builders, transactional senders, and AI-native workflows using the CLI, MCP server, or web app
- [Customer.io CLI](https://docs.customer.io/ai/cli/get-started.md): Install the `customerio/cli` agent skill and let terminal-based coding agents sign up, authenticate, and manage Customer.io workspaces
- [Customer.io MCP](https://docs.customer.io/ai/mcp/get-started.md): Connect chat-based AI tools like ChatGPT and Claude Desktop to Customer.io
- [Full documentation](https://docs.customer.io/llms-full.txt): Complete text of all documentation pages in a single file
- [Pipelines API spec](https://docs.customer.io/files/pipelines.json): OpenAPI spec for the Data Pipelines API
- [Track API spec](https://docs.customer.io/files/journeys-track.json): OpenAPI spec for the Track API
- [App API spec](https://docs.customer.io/files/journeys-app.json): OpenAPI spec for the App API
- [Webhooks spec](https://docs.customer.io/files/journeys-webhooks.json): OpenAPI spec for reporting webhooks