Block Inaccessible GitLab Merge Requests with n8n WCAG Checks

Block inaccessible GitLab merge requests with automated WCAG 2.1 checks in n8n

This n8n workflow automatically scans your GitLab merge request changes for basic WCAG 2.1 accessibility problems, then sets a GitLab commit status and maintains a single merge request comment with findings and suggested fixes—helping you prevent inaccessible code from being merged.

What this workflow does

• Triggers on merge request updates when a GitLab merge request is opened, reopened, or updated while it remains in the opened state.
• Pulls the merge request diffs via the GitLab REST API, filters to markup-related files, and determines which line numbers were added by the merge request.
• Loads full file content for each changed markup file at the merge request’s last commit SHA.
• Runs WCAG checks for common markup issues, including:
  • Missing image alt text
  • Missing form labels
  • Missing page language
  • Empty links/buttons
  • Missing iframe titles
  • Low inline color contrast
  • Positive tabindex
  • Autoplay media
• Fails or passes intelligently based on problems introduced by the merge request (or unreadable files).
• Supports an optional waiver using a configured GitLab label.
• Reports results in GitLab by setting a commit status and creating/updating one merge request comment containing detailed findings and suggested fixes.

Use cases

• Enforce accessibility gatekeeping for front-end changes before merge in a GitLab-based SaaS product.
• Reduce manual WCAG review time by catching frequent markup accessibility regressions automatically in the PR/MR workflow.
• Improve EU Accessibility Act alignment with consistent, automated checks on introduced issues.

Technical details

• Integrations: GitLab OAuth2 credential, GitLab Trigger, GitLab HTTP Request, GitLab nodes
• Logic nodes: if, set, code, switch, no op
• Behavior: Reads merge request diffs, fetches markup content at the last commit SHA, flags issues (including whether they’re in added lines), then updates GitLab commit status and a single MR comment.