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📬

Resend API

Email

Modern email API for developers — send transactional emails reliably.

Resend provides a developer-first email API. Send transactional emails, marketing campaigns, and notifications with React Email templates and real-time analytics.

Details

Auth Type
API Key (Bearer token)
Rate Limit
10 requests/second
Pricing
Free: 3,000 emails/mo
Full Docs
Step 1: Save your provider key

This is NOT your Callio key. Enter the API key from the provider's dashboard (e.g. The API key from the provider's dashboard).

API Key (Bearer token)

Get your API key at resend.com/api-keys.

Get API Credentials

Getting Started

1

Try It Instantly

Click "Try It" above to test the API in the playground

2

Add to Your Agent

Click "Add to Agent" to get your API key and integrate

Common Use Cases

Transactional email
Welcome emails
Password resets
Notifications
Marketing campaigns

💻 Code Examples

Get started quickly with these code examples in your favorite language

curl -X GET \
  'https://callio.app/api/proxy/resend/forward?target=https%3A%2F%2Fapi.resend.com%2Fendpoint' \
  -H 'Authorization: Bearer YOUR_CALLIO_KEY' \
  -H 'Content-Type: application/json'

💡 Tip: Replace YOUR_CALLIO_KEY with your actual Callio API key from the dashboard.

Ready to integrate Resend API?

Test endpoints live or generate your API key and start building in minutes

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