n8n Workflow: Post PR Preview Screenshots to GitHub

Automatically add preview screenshot results to your GitHub Pull Requests

This n8n workflow listens for a CI webhook when a PR preview is deployed, captures full-page screenshots (only for the changed routes) using Snapshot Site, and posts a single, GitHub pull request comment with a summary table, embedded previews, and any capture failures.

What this workflow does

• Receives a POST webhook from your CI containing: GitHub owner, repository, PR number, preview base URL, and a list of changed page routes to capture.
• Validates and builds URLs: generates full https:// URLs per route, removes duplicates, and enforces a configurable maximum number of pages to screenshot.
• Waits for the preview to warm up by pausing for 30 seconds before capture.
• Captures full-page screenshots via Snapshot Site using WebP output at 1280px width, with cookie banners hidden.
• Reports per-page outcomes: records each capture as success (including an image link) or failure (including the error message) without stopping the run on errors.
• Posts one GitHub comment: creates a GitHub-flavoured Markdown comment containing a results table, collapsible screenshot previews, and a list of pages that could not be captured.

Use cases

• Catch UI regressions early by sharing PR preview screenshots directly in GitHub.
• Reduce noise by capturing only changed preview routes rather than every page.
• Improve engineering feedback loops for SaaS and web apps with automated preview deployments.

Technical details

• Nodes / logic: if, set, code, wait, webhook, github
• Snapshot Site integration: requires the verified community node n8n-nodes-snapshot-site and Snapshot Site API credentials.
• GitHub integration: requires GitHub credentials with permission to create pull request comments (classic PAT with repo, or fine-grained token with Pull requests: Read and write for the target repository).