Cloudflare R2 — Plan

Complexity: Low-Medium Integration: Cloudflare R2 (S3-compatible) for ActiveStorage file uploads in production

External Setup

1. Log into Cloudflare Dashboard: https://dash.cloudflare.com
2. R2 Object Storage → Activate (free tier: 10GB storage, 10M reads/mo)
3. Create bucket: name your-app-production
4. Note Account ID (32-char hex, visible in dashboard URL)
5. Create R2 API Token: R2 → Manage R2 API Tokens → Create → "Object Read & Write" → note Access Key ID + Secret Access Key
6. Set up public custom domain:
   • R2 → bucket → Settings → Public Access → Custom Domain
   • Add cdn.yourdomain.com
   • Domain must be on Cloudflare DNS — add CNAME record
   • Enable public access
7. (Optional) Set CORS policy: R2 → Bucket → Settings → CORS → allow your app's origin
8. (Optional) Set Cache Rule: Caching → Cache Rules → aggressive caching for cdn.yourdomain.com/*

Code Changes

1. Add to Gemfile: gem "aws-sdk-s3", require: false
2. bundle install
3. Add credentials via bin/rails credentials:edit:

   cloudflare:
     r2_account_id: "your-cloudflare-account-id"
     r2_access_key_id: "your-r2-access-key-id"
     r2_secret_access_key: "your-r2-secret-access-key"
     r2_bucket: "your-bucket-name"
   

4. Add to config/storage.yml:

   cloudflare:
     service: S3
     access_key_id: <%= Rails.application.credentials.dig(:cloudflare, :r2_access_key_id) %>
     secret_access_key: <%= Rails.application.credentials.dig(:cloudflare, :r2_secret_access_key) %>
     region: auto
     bucket: <%= Rails.application.credentials.dig(:cloudflare, :r2_bucket) %>
     endpoint: https://<%= Rails.application.credentials.dig(:cloudflare, :r2_account_id) %>.r2.cloudflarestorage.com
     force_path_style: true
     public: true
   

5. Update config/environments/production.rb: config.active_storage.service = :cloudflare
6. Update CSP in config/initializers/content_security_policy.rb: add cdn.yourdomain.com to img_src
7. Dev stays on :local — no changes needed

Verification

• Upload avatar/project logo in production → appears in R2 bucket (Cloudflare dashboard)
• Images load from cdn.yourdomain.com in browser
• Image variants (thumbnails) generate correctly