JavaScript secret scanning is the process of reviewing client-side code, bundles, and source maps for sensitive data such as API keys, access tokens, internal endpoints, and hard-coded credentials. Because JavaScript is shipped to browsers, anything embedded in it may be visible to anyone who can fetch the file.
This matters in cyber security because front-end code often leaks details that server-side controls never intended to expose. Attackers use secret scanning to find reusable credentials, map hidden services, and identify cloud or third-party integrations that can be abused later. Defenders use the same technique in code review, CI pipelines, and asset audits to catch secrets before release. In practice, the goal is to treat client-side code as a disclosure surface and remove secrets from bundles, logs, and embedded configuration.