How to Send Emails from Your App
Your app needs to send signup confirmations, password resets, notifications, or reports. Resend makes it free and simple — 3,000 emails per month, no SMTP configuration.
This guide was written as of April 2026. If anything looks different, let us know.
Before you start
What you'll have at the end
A Resend API key in your .env file
Free tier
3,000 emails/month, 100/day. Next tier: $20/mo.
Create a Resend account
Go to resend.com and sign up. Free plan, no credit card required.
Get your API key
In the Resend dashboard, go to API Keys. Click Create API Key. Give it a name (like "my-app") and copy the key.
Add to your .env file
Add this to your .env file:
RESEND_API_KEY=re_your-api-key-here
Verify your domain (optional)
By default, emails come from a generic address. To send from [email protected], go to Domains in the Resend dashboard, add your domain, and follow the DNS verification steps. This makes your emails look professional and reduces spam filtering.
Verify it works
Your Resend dashboard should show your API key. You have one new line in your .env file. Your AI tool can now send emails from your app.
Tell Your AI Tool
Copy this prompt and paste it into your AI coding tool. It tells your AI exactly what credentials you just set up.
I've set up Resend for sending emails. My API key is in my .env file as RESEND_API_KEY. Add email sending to my app for [signup confirmations / password resets / notifications / reports].
Paste the prompt into the chat panel (Cmd+L or Ctrl+L). Cursor can also read your .env file directly — if your credentials are there, it already knows.
YepAPI Tip
Automate email reports — YepAPI pulls your weekly SEO data, your AI tool formats it, Resend delivers it to your inbox.
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Resend Email — FAQ
A transactional email is an automated email triggered by a user action — password resets, order confirmations, welcome emails. It's different from marketing emails (newsletters, promotions). Resend handles transactional emails.
Yes. The free plan gives you 3,000 emails per month and 100 per day. Enough for any side project. If you outgrow it, the next tier is $20/month.
No, but it's recommended. Without a custom domain, your emails come from a generic address and are more likely to hit spam filters. With your own domain, emails come from [email protected] and look professional.
Resend is newer, simpler, and developer-friendly with a modern API. SendGrid is older and more complex. For vibe coded projects, Resend is the easier choice.
Start vibe coding with one API key.
One API key. 100+ endpoints. Yep, that's it.