What is cf-pr-preview-action?

cf-pr-preview-action is a GitHub Action that gives every pull request its own isolated, ephemeral Cloudflare preview: a per-PR Worker wired to a per-PR D1, KV, and R2, deployed to a workers.dev URL and torn down automatically when the PR closes or merges.

It derives the preview from your existing wrangler.jsonc — no duplicated config — renames every resource to a per-PR namespace, and lets you run whatever you want against the isolated environment (migrations, seed, smoke tests) via command hooks.

PR opened / pushed   ──▶  provision per-PR D1 + KV + R2  ──▶  deploy Worker  ──▶  💬 comment w/ URL
PR closed / merged   ──▶  delete Worker + D1 + KV + R2   ──▶  💬 comment updated

Why

Testing a Cloudflare Workers app that uses D1/KV/R2 usually means sharing one staging environment — PRs stomp on each other's data, and there's no clean "throwaway" stack per change. This action gives each PR a complete, isolated copy of your stack that behaves like production, then deletes it when you're done.

What makes it different

Plenty of actions deploy a Worker preview per PR. This one isolates the stateful layer too:

• Per-PR D1 database (with migrations applied)
• Per-PR KV namespaces
• Per-PR R2 buckets
• Optional sync of your dev D1 + R2 into each preview, so it starts with realistic data
• Automatic teardown of all of it on PR close

Next steps

• Getting started — add it to your repo in one workflow file
• Syncing dev data — mirror your dev D1 + R2 into previews
• How it works — the deploy and teardown pipelines
• Inputs & outputs — every option