How is merge request verification performed in the free version of GitLab?

In the free version of GitLab, merge request checks are performed using built-in mechanisms:

• Automatic triggering of CI/CD pipelines if .gitlab-ci.yml is configured — for build, test, and other checks.
• Webhooks and integrations with external services.
• Manual or automatic code review through comments and discussions.

However, some advanced features, such as mandatory merge rules (merge checks), extended security policies, and automatic license-based checks, are only available in paid versions.

Thus, in the free version, the main check is setting up and running CI/CD pipelines, as well as manual code review.