What intermediate tool do we use for build validation in CI/CD when creating changes as a pull request?

In most modern pipelines we use an intermediate CI/CD tool such as GitHub Actions, GitLab CI, or Jenkins to perform build validation on pull requests. When a PR is opened or updated, the tool automatically triggers a workflow that checks out the code, installs dependencies, runs unit tests, builds artifacts, and optionally performs static analysis or security scans. The results are posted back to the PR as a status check, and the merge is blocked until all checks pass. This approach ensures that every change is automatically validated before it reaches the main branch, reducing bugs and maintaining code quality.