TL;DR
Cloudflare is one of the most security-focused platforms available. Their developer platform (Workers, Pages, R2) inherits world-class DDoS protection and security infrastructure. Workers use V8 isolates for fast, secure execution. Being a security company at their core, they have strong defaults and practices throughout.
What is Cloudflare?
Cloudflare provides security and performance services for websites, plus a developer platform including Workers (edge compute), Pages (static/SSR hosting), R2 (object storage), D1 (SQLite), KV (key-value store), and more. Powers a significant portion of the internet.
Our Verdict
What's Good
- World-class DDoS protection
- V8 isolate security model
- SOC 2, ISO 27001 certified
- Encrypted secrets (Wrangler)
- Built-in WAF available
What to Watch
- Complex permissions model
- API token scope management
- R2 bucket access configuration
Workers Security
V8 Isolates: Workers run in V8 isolates, the same technology Chrome uses to isolate tabs. Each Worker execution is isolated with minimal overhead.
| Aspect | Workers (V8 Isolates) | Traditional Serverless |
|---|---|---|
| Isolation | V8 isolate per request | Container per function |
| Cold start | ~0ms | 100ms-seconds |
| Memory isolation | Complete | Complete |
| Attack surface | V8 engine only | Container + runtime |
Pages Security
Cloudflare Pages for static sites and SSR:
- Automatic HTTPS: All deployments
- Preview deployments: Unique URLs per branch/commit
- Access policies: Protect previews with Cloudflare Access
- Build environment: Isolated builds with encrypted secrets
Preview Protection: Use Cloudflare Access to require authentication for preview deployments, preventing public exposure of staging environments.
Storage Security
| Product | Security Features |
|---|---|
| R2 (Object Storage) | Encryption at rest, signed URLs, bucket policies |
| KV (Key-Value) | Namespace isolation, encrypted at rest |
| D1 (SQLite) | Database-level isolation, encrypted |
| Durable Objects | Per-object isolation, consistent state |
API Token Management
- Scoped tokens: Create tokens with minimal required permissions
- Zone restrictions: Limit tokens to specific domains
- IP restrictions: Limit token usage by IP
- Expiration: Set token expiry dates
Is Cloudflare safe for production?
Cloudflare is one of the safest platforms available. As a security company first, they have world-class DDoS protection, multiple compliance certifications, and a battle-tested infrastructure that handles a huge portion of internet traffic.
Are Workers secure?
Yes, Workers use V8 isolates which provide strong security boundaries. Each request runs in isolation. The V8 engine is one of the most security-scrutinized pieces of software due to its use in Chrome.
How do I secure R2 buckets?
R2 buckets are private by default. Use signed URLs for temporary access, bucket policies for fine-grained control, and never expose bucket credentials in client-side code.