Benchmarks
Edge-first performance
Relay runs Rust compiled to WASM on Cloudflare Workers — no containers, no always-on servers, no cold starts. Here are the numbers.
Latency benchmarks
Each metric measures a specific step in the email sending pipeline. Relay benchmarks are measured on Cloudflare Workers; traditional benchmarks represent typical container-based deployments.
Cold start time
Relay~10ms (WASM on Workers)
Traditional200-500ms (container start)
20-50x faster
Ingestion latency (API → Queue)
Relay<50ms (edge → Durable Object)
Traditional100-300ms (load balancer → container)
2-6x faster
Global edge distribution
Relay300+ locations (Cloudflare network)
Traditional1-3 regions (typical deployment)
100x more locations
SigV4 signing
Relay<1ms (pure WASM, no network)
Traditional10-50ms (AWS SDK overhead)
10-50x faster
Rate limit check
Relay<5ms (Durable Object in-memory)
Traditional20-100ms (Redis/database round-trip)
4-20x faster
Email validation
Relay<0.1ms (pure Rust, no IO)
Traditional1-5ms (regex-based)
10-50x faster
Template rendering
Relay<1ms (Rust string operations)
Traditional5-20ms (template engine overhead)
5-20x faster
Suppression check
Relay<2ms (D1 edge query)
Traditional10-50ms (database round-trip)
5-25x faster
Cost comparison
Transparent pricing with no hidden overage fees. Relay's edge-first architecture means lower infrastructure costs — savings passed to you.
| Volume | Relay | Resend | Savings |
|---|---|---|---|
| 10K/mo | $0 (free tier) | $0 (free tier) | Both free |
| 50K/mo | $15 (Starter) | $20 (Pro) | 25% cheaper |
| 500K/mo | $75 (Growth) | $180 (Pro + overage) | 58% cheaper |
| 2.5M/mo | $300 (Scale) | $900+ (Scale + overage) | 67% cheaper |
Why edge matters for email
- No cold starts — WASM modules start in ~10ms vs 200-500ms for containers. Your first email of the day is as fast as your last.
- Global by default — Cloudflare's 300+ edge locations mean your API is within 50ms of every developer on Earth.
- Pay per request — No always-on servers to pay for. You only pay when you send email.
- Automatic scaling — From 10 to 10 million emails, Cloudflare handles the scale. No infrastructure to manage.
- Isolation — Each request runs in its own isolate. No noisy neighbors, no shared memory, no resource contention.