# Introduction

Needle is an outbound engine for revenue teams. Keep a list of leads, add connected accounts for LinkedIn and Instagram, and enroll people in campaigns. The same work is available in the dashboard, over the REST API, and as MCP tools.

See [Authentication](/docs/authentication) for API keys.

## Core concepts

- [Organizations](/docs/organizations): The workspace that owns leads, campaigns, and connected accounts.
- [Leads](/docs/leads): People you can enroll in a campaign.
- [Campaigns](/docs/campaigns): Sequences this organization is running.
- [Enrollments](/docs/enrollments): A lead moving through a campaign sequence.
- [Connected Accounts](/docs/connected-accounts): LinkedIn and Instagram senders this organization reaches out from.
- [Suppressions](/docs/suppressions): People and companies on the do-not-contact list.
- [Events](/docs/events): Activity across campaigns, leads, and connected accounts.
- [Places](/docs/places): Companies and locations you can turn into lead lists.
- [Compose](/docs/compose): Preview an AI-written message before you send it.
- [Agents](/docs/agents): Personal agents that work in Slack and Teams.

## REST API

The public API lives under `/api/v1`. See the [API Reference](/docs/api-reference/introduction) for endpoints, parameters, and schemas.

## MCP

Connect an agent at `/mcp/v1` with the same API key. Listing tools does not require a key; calling them does. See the [MCP catalog](/docs/mcp/introduction) for every tool.

## OpenAPI

The machine-readable spec is at `/api/v1/openapi`. Use it to generate clients or import the API into your own tooling.

## For agents

Start with the [onboarding skill](/docs/agent-onboarding). It routes to MCP, the REST API, credentials, and common outbound workflows.