---
title: Authentication
description: How to authenticate with Composio APIs using project and organization API keys
keywords: [API authentication, API key, x-api-key, x-org-api-key, Composio authentication, authorization]
---

Every Composio API request authenticates with an API key. Send the key in a request header and Composio resolves it to your project or organization.

## Project API key

A project API key authenticates to one project with full access. Send it in the `x-api-key` header.

Get it from the dashboard: sign in to [composio.dev](https://composio.dev), open **Settings → Project Settings**, and copy the key from the **API Keys** section.

## Organization API key

An organization API key authenticates across every project in your organization. Send it in the `x-org-api-key` header.

Get it from the dashboard: open **Organization Settings → General Settings** and copy a token under **Organization Access Tokens**.

## Using the API key

Include your API key in the request header:

```bash
curl https://backend.composio.dev/api/v3/tools \
  -H "x-api-key: $COMPOSIO_API_KEY"
```

For organization-level endpoints:

```bash
curl https://backend.composio.dev/api/v3/org/projects \
  -H "x-org-api-key: $COMPOSIO_ORG_API_KEY"
```

<Cards>
  <Card title="Errors" href="/reference/v3/errors">
    Understanding API error responses
  </Card>
  <Card title="Rate Limits" href="/reference/v3/rate-limits">
    API rate limits by plan
  </Card>
</Cards>