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1

Sign up and create a Paubox account

It’s free to sign up and to send up to 300 emails per month with Paubox Email API. Visit our sign up page and create an account.
Note:If you send more than 300 emails in one month, you will be automatically moved to the appropriate pricing tier and billed the annual cost.
2

Add and verify your domain

Once you have a Paubox account, go to the Paubox Email API > Settings page and add the domain you’ll be sending from.Paubox will display a TXT record to add to your domain’s DNS provider (e.g., Route 53, Cloudflare, GoDaddy). Copy the verification string and add it as a new TXT record at your DNS provider, then return to the Settings page and click Verify.
Tip:Most DNS providers propagate TXT records within a few minutes, but allow up to 48 hours. If verification fails immediately, wait a few minutes and try again.
3

Generate an API key

From the Paubox Email API > Settings page, click on the domain you would like to generate an API key for, then press the Add API Key button. Give the key a description and a new key will be generated upon submission.You can generate several API keys to use in different applications as needed. Make sure you save your key because if you lose it you will have to generate a new one.Note the customer endpoint shown on the same Settings page. It takes the form:
https://api.paubox.net/v1/YOUR_USERNAME
You will use this base URL in every API request.
4

Send your first email

Use the following curl command to send a test email. Replace YOUR_USERNAME, YOUR_API_KEY, and the from address with your actual values. The from address must match your verified domain.
curl --request POST \
  --url https://api.paubox.net/v1/YOUR_USERNAME/messages \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "data": {
      "message": {
        "recipients": ["recipient@example.com"],
        "headers": {
          "subject": "Hello from Paubox",
          "from": "sender@yourdomain.com"
        },
        "content": {
          "text/plain": "Hello world",
          "text/html": "<html><body><h1>Hello world</h1></body></html>"
        }
      }
    }
  }'
What success looks like:A 200 OK response confirms your message was accepted for delivery:
{
  "sourceTrackingId": "3d38ab13-0af8-4028-bd45-52e882e0d584",
  "data": "Service OK"
}
Save the sourceTrackingId; you can use it to check delivery status later.
5

Integrate via SDK

Official SDKs handle authentication and request formatting for you. Choose your language:
Prefer the terminal? See the CLI quickstart to send email without writing code.

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Next steps

Track message status

Check delivery status using a sourceTrackingId

Send attachments

Add files to your messages via the REST API

MCP server

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