Snyk is a platform that helps developers test their open source dependencies for known vulnerabilities, and create a free account to start importing projects from GitHub and testing them for security issues. To get started, users need to grant Snyk access to their email address associated with their GitHub account and select the project they want to test from their list of repositories. Once imported, Snyk reads the package.json manifest file and builds a dependency graph, testing against the Snyk vulnerability database and providing a full report. The platform also offers features like automatic Fix Pull Requests for remediation, allowing users to identify and fix security issues in their projects.