> ## Documentation Index
> Fetch the complete documentation index at: https://docs.esperr.com/llms.txt
> Use this file to discover all available pages before exploring further.

# API Keys

> Credentials that allow sending systems to authenticate with a tenant.

## What this page is for

Use this page when a system needs permission to send events into Esper.

Typical examples:

* Your web application.
* Your backend API.
* A partner integration.
* An internal service.

## What you configure for an API key

When creating a key, the console collects:

* `name`: The label operators see in the dashboard.
* `trust_level`: The trust level for requests signed by this key.
* `secret`: The shared secret used to authenticate requests.

## How this connects to the rest of the system

* Ingest clients authenticate with API keys.
* The Esper CLI can use the same key when `api_key` is configured in
  `~/.esper/config.yaml` or passed through `esper init --api-key`.
* Events are attributed to the tenant associated with the key.

<Tip>
  **Cloud Onboarding**

  For `cloud`, the API key is the main customer credential. The customer
  sends traffic with `x-esper-api-key` and waits for Esper to return the current
  mitigation context.
</Tip>

<Info>
  **API Keys Still Need an Integration Point**

  The API key does not appear in requests by itself. The customer needs
  application code, middleware, a proxy, or a platform integration that can add
  the header on outbound traffic to Esper.
</Info>

This means API keys remain the first operational link between tenant traffic and the policy builder.