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

# Signals

> Registers signal sinks and subscriptions in Cognite Data Fusion using the beta REST API.

A signal is a notification that something has occurred in a CDF process. The **Signals API** lets you register **signal sinks** where those signals are delivered, and define **signal subscriptions** that filter which signals go to which sinks.

Signals are intended for event-style notifications and integrations—for example surfacing workflow failures, extractor health, or other operational events to external systems.

## Concepts

* **Sinks** — Delivery targets for signals: an **email** sink or a **user** sink. Create, list, update, and delete sinks through the sinks endpoints.
* **Subscriptions** — Rules that select which signals to receive and which sink should receive them. Manage subscriptions with the subscriptions endpoints.
* **Listing signals** — Retrieve published signals with the list endpoint when you need to inspect or debug traffic.

## Configure as code

If you use the **Cognite Toolkit**, you can represent sinks and subscriptions as YAML resources under a `signals/` directory. See the toolkit [resource library](/cdf/deploy/cdf_toolkit/references/resource_library#signals) for supported kinds and examples.

<Info>
  The **stable** (`20230101`) API reference does not include Signals. Use the **beta** or **alpha** API reference for Signals concepts and endpoint documentation. Send `cdf-version: beta` on requests. For how preview APIs relate to stable, see [Beta API reference](/api-reference/concepts/20230101-beta/beta-api).
</Info>

## Rate and concurrency limits

Signals share the general CDF request budgets. For limit types and throttling behavior, see [API rate limits](/api-reference/concepts/20230101-beta/rate-limits).