Early bird — first 10 customers at $75

Resend pricing.
SMTP prices.
Cut your bill by 90%.

Drop RelayCut on your VPS, change one URL in your app. Works with any HTTP client, any language, any SDK — or just let your AI agent set it up using the included AGENTS.md.

Read what's included — $75 → See how it works
Resend · 100k emails
$85/mo
→
RelayCut + Brevo
$9/mo
→
Monthly savings
$76/mo
How it works

Three steps. One URL change.

Your app keeps using the Resend SDK. RelayCut just intercepts the call.

01
🖥️

Drop on your VPS

Unzip, fill in one .env file, run docker compose up -d. Done in under 5 minutes.

02
🔗

Change one URL

Point your Resend baseURL from api.resend.com to your-vps-ip:3000. Nothing else changes.

03
💸

Pay SMTP prices

Every email routes through Brevo, Mailgun, or Postmark. RelayCut pays for itself in under 30 days.

04
🤖

Let your agent handle it

Point Cursor, Claude, or any AI agent at the included AGENTS.md — it has everything the agent needs to integrate RelayCut into your codebase in one shot.

The only change in your codebase
−baseURL: "https://api.resend.com"
+baseURL: "http://YOUR_VPS_IP:3000"
That's it. Your Resend SDK call works completely unchanged.
Cost savings

Real numbers. Real savings.

RelayCut pays for itself in under 30 days for almost every use case.

Emails / month Resend cost RelayCut + Brevo You save Payback period
50,000 ~$20/mo ~$0/mofree tier $20/mo < 4 months
100,000 ~$85/mo ~$9/mo $76/mo < 1 month
500,000 ~$400/mo ~$25/mo $375/mo ~1 week

* Brevo free tier: 300 emails/day (~9k/month). Paid plans from $9/mo for 120k emails.

SMTP Providers

Works with any SMTP. We recommend Brevo.

Provider-agnostic. Pick the one that fits your volume.

Recommended
Brevo
300 emails/day free
From $9/mo — 120k emails
Easiest setup. Most users start here.
brevo.com →
Mailgun
100 emails/day trial
From $15/mo — 50k emails
Great for high-volume senders.
mailgun.com →
Postmark
100 emails/mo free
From $15/mo — 10k emails
Best deliverability. Premium tier.
postmarkapp.com →
Any SMTP
Your own server
Your own cost
AWS SES, self-hosted Postfix, or any SMTP endpoint.
Bring your own
What you get

Honest about what's in. Honest about what's not.

Read this before buying. No surprises, 14-day conditional refunds only.

✅ What's Included
  • ✓
    Single email sendPOST /emails — from, to, subject, html, text
  • ✓
    Batch sending (up to 100)POST /emails/batch — concurrent via Promise.all()
  • ✓
    CC, BCC, Reply-ToAll addressing fields fully supported
  • ✓
    Attachments (Base64)Pass through any file your app sends
  • ✓
    Any SMTP providerBrevo, Mailgun, Postmark, or any SMTP endpoint
  • ✓
    Docker + docker-composeNo Node.js install. No PM2. Just Docker.
  • ✓
    Auto-restart on crash / rebootrestart: always — set once, runs forever
  • ✓
    API key authenticationNobody else can use your relay
  • ✓
    Full README + troubleshooting guideCopy-paste commands for every step
  • ✓
    AGENTS.md — AI agent context filePoint Cursor, Claude or any agent at this file to integrate RelayCut instantly
⚠️ What's NOT Included
  • ✗
    Webhooks importantNo bounce/delivery/open/click events. If your app depends on Resend webhooks, this is not the right fit.
  • ✗
    Email schedulingStateless by design — no queue or database
  • ✗
    Idempotency keysRequires a database — out of scope for v1
  • ✗
    Dashboard / analyticsNo open rates or click tracking — use your SMTP provider's dashboard
  • ✗
    Marketing / broadcast emailsTransactional only
  • ✗
    Contact / audience managementNo list management
  • ✗
    Inbound emailOutbound SMTP only
  • ✗
    Automatic HTTPS / SSLOptional Nginx setup — guide in README
Pricing

One-time payment. Yours forever.

No subscription. No per-email fees. Pay once, deploy anywhere.

Early Bird — First 10 customers
$90 $75
one-time payment
  • ✓ server.js proxy (single + batch send)
  • ✓ Dockerfile + docker-compose.yml
  • ✓ .env.example with step-by-step comments
  • ✓ Full README with copy-paste setup guide
  • ✓ Troubleshooting for every common error
  • ✓ Works with Brevo, Mailgun, Postmark, any SMTP
  • ✓ AGENTS.md included — let Cursor or Claude set it up for you
  • ⚠ 14-day conditional refunds — see terms for details
I've read what's included — Buy for $75 →

Price rises to $90 after first 10 sales. Checkout via Lemon Squeezy.

⏳ 14-Day Conditional Refund

This is a downloadable ZIP of full source code. We offer a 14-day conditional refund if the product fails to fulfill its stated capabilities. Please read the limitations section carefully before purchasing.

📦 What you download

A .zip with 6 files: server.js, Dockerfile, docker-compose.yml, .env.example, package.json, README.md. Unzip on your VPS, fill in one file, run one command.

⚡ Payback in under 30 days

At 100k emails/month you save $76/mo. RelayCut pays for itself in the first billing cycle.

🔌 Not affiliated with Resend

Independent software. Not affiliated with, endorsed by, or related to Resend Inc.