---
title: Connectors
description: How Actions authenticate to outside systems without holding their credentials.
---

A **Connector** authenticates an Action's requests to an outside system, so the Action's code never holds the credential. A Connector does only authentication: it provides no Tables or Datasets.

## Placeholders

A Connector has a fixed, non-secret **placeholder**, `__TRACTORBEAM_CONNECTOR_<NAME>__`. An Action puts the placeholder in a header of a request to one of the Connector's origins, and Tractorbeam replaces it with the connection's credential.

## Connections

A **connection** is the one authorized account of a Connector, which supplies the credential for each request. Each Connector has one connection, the Workspace's.

A **credential** is the secret value, such as an API key or an OAuth access token, that a connection or a Secret supplies. A rotated key or a refreshed token is a new credential for the same connection.