SonarQube GitLab CI Integration: Configuration Guide

Every merge request that reaches your default branch without static analysis is a gamble - a potential bug, vulnerability, or code smell that compounds into technical debt over time. Integrating SonarQube with GitLab CI/CD eliminates that gamble by running automated code quality checks on every push and merge request. Unlike GitHub Actions where SonarSource provides an official action, GitLab CI integration relies on the SonarScanner CLI run inside a Docker container, giving you more control over the pipeline configuration but requiring a bit more setup work. This guide covers every aspect of setting up SonarQube in GitLab CI. You will learn how to write the .gitlab-ci.yml configuration, configure CI/CD variables, enable merge request decoration, enforce quality gates, cache scanner data, handle monorepo setups, choose between SonarQube Cloud and self-hosted for GitLab, and troubleshoot the most common issues. Every configuration example shown here is production-ready and can be adapte