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5 minute read - The free plan includes 5,000 emails/month - perfect for getting started!

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Prerequisites

A Unosend account (free to create)
cURL or any HTTP client (for testing)
A verified domain (optional, but recommended)

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Step 1: Create an Account

Sign up for a free Unosend account at unosend.co/signup. No credit card required.
The free plan includes 5,000 emails/month - perfect for getting started!

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Step 2: Get Your API Key

Navigate to API Keys in your dashboard and click “Create API Key”. Your API key will start with the un_ prefix.
Your API Key
un_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Important: Copy and save your API key immediately - it’s only shown once! Keep it secure and never expose it in client-side code.

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Step 3: Add a Domain

Go to Domains in your dashboard and add your sending domain. You’ll need to add DNS records to verify ownership.
cURL
curl -X POST https://api.unosend.co/domains \
  -H "Authorization: Bearer un_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"domain": "yourdomain.com"}'
Add the returned DNS records to your domain provider, then verify:
cURL
curl -X POST https://api.unosend.co/domains/{domain_id}/verify \
  -H "Authorization: Bearer un_your_api_key"

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Step 4: Send Your First Email

Once your domain is verified, send your first email using the REST API. Works with any programming language! 
curl -X POST https://api.unosend.co/emails \
  -H "Authorization: Bearer un_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "hello@yourdomain.com",
    "to": ["recipient@example.com"],
    "subject": "Hello from Unosend!",
    "html": "<h1>Welcome!</h1><p>This is your first email sent with Unosend.</p>"
  }'

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Response

200 OK
{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "from": "hello@yourdomain.com",
  "to": ["recipient@example.com"],
  "status": "queued",
  "created_at": "2024-01-15T10:30:00.000Z"
}

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Next Steps

Learn Authentication

Understand API key security best practices

Domain Verification

Set up SPF, DKIM, and DMARC for better deliverability

Explore the API

See all available API endpoints

Set Up Webhooks

Receive real-time email event notifications