GitLab CI Validator

The Online GitLab CI Validator analyzes a GitLab CI configuration to verify syntactic correctness and semantic validity of jobs, pipelines, and rules. It accepts a YAML snippet or an entire .gitlab-ci.yml file and returns precise diagnostics that help ensure pipelines execute as intended. It detects invalid syntax, misordered stages, and improper keyword usage, reducing time spent on debugging in CI workflows. By validating both common YAML pitfalls and GitLab-specific semantics, it supports teams that rely on automated pipelines for deployments, tests, and security checks.
The tool parses YAML into a structured representation, applies the GitLab CI schema, and then performs rule-aware checks on jobs, includes, extends, image, services, artifacts, cache, and needs. For example, if a job references a non-existent stage or uses "needs" for a missing job, the validator flags the issue with location hints and suggested fixes. It also checks syntax compatibility across GitLab Runner versions.
Targeted at developers, DevOps engineers, and platform teams building CI pipelines in GitLab, it differentiates itself by providing fast, deterministic diagnostics, actionable suggestions, and version-aware checks; supports partial inputs; returns machine-readable diagnostics (JSON) in addition to human-readable messages; and offers incremental validation for changed sections. Core features include syntax lint, semantic checks, cross-job validation, and exportable reports. Use cases include pre-commit validation, PR checks, and pre-merge CI validation.
The validator helps reduce cycle time, increases pipeline reliability, and improves collaboration between developers and operations teams.