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# Using sandbox mode
Use sandbox mode to test transactional email requests without sending actual emails. This lets you validate your API integration in a safe testing environment.
## How it works
Add the `X-Sib-Sandbox` header with the value `drop` to your request. In sandbox mode:
* No emails are sent to recipients
* No email logs are created in your Brevo account
* You receive a success response indicating the API endpoint is working correctly
## Example request
```bash
curl --request POST \
--url https://api.brevo.com/v3/smtp/email \
--header 'accept: application/json' \
--header 'api-key: YOUR_API_KEY' \
--header 'content-type: application/json' \
--data '{
"sender": {
"name": "Sender Name",
"email": "sender@example.com"
},
"headers": {
"X-Sib-Sandbox": "drop"
},
"to": [
{
"email": "recipient@example.com",
"name": "Recipient Name"
}
],
"htmlContent": "Confirm your email
Please confirm your email address by clicking on the link below
",
"textContent": "Please confirm your email address by clicking on the link https://text.domain.com",
"subject": "Login Email confirmation"
}'
```
## Response
You receive a `201` success response with a `messageId`, but no email is sent:
```json
{
"messageId": "<20x31xxx02xx.2004x1008xx@smtp-relay.mailin.fr>"
}
```
Sandbox mode only validates the API request format. To test actual email delivery, send emails without the sandbox header.