GitHub PR Reviewer Assignment by File Ownership (Supabase + Slack)

Automatically assign GitHub PR reviewers by file ownership—then notify them in Slack

This n8n workflow listens to GitHub pull request webhooks, figures out which files changed, selects the best-fit reviewers from your Supabase roster by file path ownership (and fairness via last-assigned time), requests review in GitHub, and sends a direct message to each reviewer in Slack.

What this workflow does

• Receives GitHub PR webhooks and extracts PR details.
• Processes only relevant PRs: newly opened, non-draft pull requests, and skips PRs created by bot accounts.
• Reads changed files via the GitHub API.
• Loads your reviewer roster from Supabase and matches reviewer owned paths against the PR’s changed file paths.
• Filters and prioritizes: excludes the PR author, then selects up to a configured maximum number of reviewers, prioritizing those with the least recently assigned timestamp.
• Requests reviews in GitHub for the selected reviewers.
• Notifies reviewers in Slack with the PR title, author, and link—then updates each reviewer’s last-assigned timestamp in Supabase.
• If no matching reviewers are found, the workflow stops its assignment process and records the “no reviewers” branch internally.

Use cases

• Route reviews to domain experts automatically (e.g., frontend vs. backend folders) using file ownership rules.
• Reduce review bottlenecks by spreading assignments fairly based on last-assigned time.
• Keep teams aligned: reviewers get an immediate Slack DM when they’re requested on a GitHub PR.
• Support SaaS and internal engineering orgs that need consistent PR triage without manual assignment.

Technical details

• GitHub: webhook ingestion (POST to /github-pr-webhook), GitHub API for PR files and requesting reviewers
• Supabase: reviewer roster + last-assigned timestamp tracking
• Slack: direct Slack messages to selected reviewers
• n8n nodes/logic mentioned: if, set, code, no op, merge, slack

Set your GitHub token (read PR files + request reviewers), repository owner/name, and connect Supabase and Slack—then let file ownership drive who gets the review.