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Comparison10 min read

Relay vs Resend vs Postmark: An Honest Comparison

We're not afraid to say where competitors are stronger. Here's a straight comparison of architecture, features, pricing, and developer experience.

Relay Team

We'll say it up front: Resend and Postmark are excellent products. We respect both teams and what they've built. Here's an honest comparison — including where the others are stronger.

Architecture

All three services ultimately rely on AWS SES for sending. The difference is what sits in front of it:

  • Relay — Cloudflare Workers (edge) + WASM. Global, per-request billing, ~50ms latency.
  • Resend — AWS infrastructure. Regional, container-based.
  • Postmark — Own infrastructure since 2010. Regional, mature.

Relay's edge-first approach means lower latency and no cold starts. Postmark has the longest track record. Resend has the most polished developer ecosystem.

Developer experience

Resend wins here — React Email, 8 SDKs, beautiful docs. It's the gold standard for DX.

Relay's approach is different: no SDK needed. Plain HTTPS with a Bearer token. Works from any language, any runtime, any environment. Some developers prefer this simplicity.

Postmark's docs are solid and battle-tested.

Pricing

  • Relay — Free tier of 10,000/month, then plans from $15/month with overage from $0.50–$0.90 per 1,000 emails depending on plan.
  • Resend — Free tier of 3,000/month, then tiered plans starting at $20/month.
  • Postmark — Free tier of 100/month, then $1.25/1k (expensive at volume).

Relay's free tier is the most generous, and the per-1k overage rate drops as you move up plans.

Deliverability

Postmark has the strongest deliverability reputation — they've been at it since 2010. Resend is strong too. Relay is newer but benefits from SES's infrastructure plus our auto-pause circuit breaker.

Where Relay is stronger

  • Edge-first architecture (no one else does this)
  • Free tier (10k/month vs 3k for Resend, 100 for Postmark)
  • BYODKIM (one TXT record)
  • Auto-pause circuit breaker
  • AI Design Studio
  • MCP endpoint for AI agents

Where competitors are stronger

  • Resend — DX, React Email, ecosystem maturity
  • Postmark — Deliverability track record, brand trust

Check our full comparison table for all features side by side.