How to Use Brevo APIs for SMS Marketing ?

TL;DR

Brevo APIs let you send marketing emails, transactional emails, and SMS messages programmatically. You authenticate with an API key, send requests to api.brevo.com, and use webhooks to track delivery and engagement. For testing, use Apidog to validate payloads, test webhook handlers, and ensure your integration handles bounces and unsubscribes correctly.

Introduction

Brevo (formerly Sendinblue) processes millions of emails daily for over 500,000 businesses. It handles marketing campaigns, transactional emails, SMS marketing, and automation workflows.

Email APIs seem simple - send a message, done. But production email systems need to handle bounces, spam complaints, unsubscribes, and delivery timing. Brevo manages this complexity so you don’t have to.

The API covers three main use cases:

Marketing campaigns - Bulk emails to contact lists
Transactional emails - Password resets, order confirmations, notifications
SMS messages - Verification codes, alerts, marketing texts

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If you’re integrating email into your app, Apidog helps you test templates, validate webhook payloads, and ensure your integration works across email clients. You can mock Brevo’s responses during development and test error handling without sending real emails.

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Authentication and setup

Get an API key

Log into Brevo
Go to SMTP & API → API Keys
Create a new key with appropriate permissions
Store it securely

The API key goes in the api-key header:

curl -X GET "https://api.brevo.com/v3/account" \
  -H "accept: application/json" \
  -H "api-key: your-api-key-here"

API base URL

All requests go to:

https://api.brevo.com/v3/

Rate limits

Brevo limits requests by plan:

Free: 300 requests/minute
Starter: 600 requests/minute
Business: 1200 requests/minute

Check the X-RateLimit-Remaining header to track usage.

Sending transactional emails

Transactional emails are individual messages triggered by user actions. Think password resets, order confirmations, welcome emails.

Send a simple email

curl -X POST "https://api.brevo.com/v3/smtp/email" \
  -H "accept: application/json" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "sender": {
      "name": "Your App",
      "email": "noreply@yourapp.com"
    },
    "to": [
      {
        "email": "user@example.com",
        "name": "John Doe"
      }
    ],
    "subject": "Welcome to Our Platform",
    "htmlContent": "<html><body><h1>Welcome!</h1><p>Thanks for signing up.</p></body></html>",
    "textContent": "Welcome! Thanks for signing up."
  }'

Response:

{
  "messageId": "<20260324123456.123456@relay.brevo.com>"
}

Using templates

Create templates in Brevo’s visual editor, then send by ID:

curl -X POST "https://api.brevo.com/v3/smtp/email" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "templateId": 15,
    "to": [
      {
        "email": "user@example.com",
        "name": "John Doe"
      }
    ],
    "params": {
      "name": "John",
      "order_number": "ORD-12345",
      "tracking_url": "https://tracking.example.com/ORD-12345"
    }
  }'

Template variables use double braces:

<p>Hi {{params.name}},</p>
<p>Your order {{params.order_number}} has shipped.</p>
<p><a href="{{params.tracking_url}}">Track your package</a></p>

Send with attachments

const response = await fetch('https://api.brevo.com/v3/smtp/email', {
  method: 'POST',
  headers: {
    'api-key': process.env.BREVO_API_KEY,
    'content-type': 'application/json'
  },
  body: JSON.stringify({
    sender: { name: 'Your App', email: 'noreply@yourapp.com' },
    to: [{ email: 'user@example.com' }],
    subject: 'Your Invoice',
    htmlContent: '<p>Please find your invoice attached.</p>',
    attachment: [
      {
        name: 'invoice.pdf',
        content: base64EncodedPdfContent
      }
    ]
  })
})

Marketing campaigns

Marketing emails go to lists of contacts. Brevo handles unsubscribe links, scheduling, and analytics.

Create a campaign

curl -X POST "https://api.brevo.com/v3/emailCampaigns" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "name": "March Newsletter",
    "subject": "What'\''s New in March",
    "sender": {
      "name": "Your Brand",
      "email": "newsletter@yourbrand.com"
    },
    "type": "classic",
    "htmlContent": "<html><body>Newsletter content here...</body></html>",
    "recipients": {
      "listIds": [12, 15]
    },
    "scheduledAt": "2026-03-25T09:00:00+00:00"
  }'

Send immediately

curl -X POST "https://api.brevo.com/v3/emailCampaigns/{campaignId}/sendNow" \
  -H "api-key: your-api-key"

Get campaign statistics

curl -X GET "https://api.brevo.com/v3/emailCampaigns/{campaignId}" \
  -H "api-key: your-api-key"

Response includes:

{
  "statistics": {
    "delivered": 4850,
    "opened": 1455,
    "clicked": 291,
    "unsubscribed": 12,
    "bounces": 150
  }
}

Contact management

Contacts are the people you send emails to. Organize them into lists and add custom attributes.

Create a contact

curl -X POST "https://api.brevo.com/v3/contacts" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "email": "new.user@example.com",
    "attributes": {
      "FIRSTNAME": "Jane",
      "LASTNAME": "Smith",
      "PLAN": "premium"
    },
    "listIds": [12, 15],
    "updateEnabled": true
  }'

The updateEnabled: true flag updates existing contacts instead of failing.

Get contact details

curl -X GET "https://api.brevo.com/v3/contacts/user@example.com" \
  -H "api-key: your-api-key"

Add to list

curl -X POST "https://api.brevo.com/v3/contacts/lists/12/contacts/add" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "emails": ["user1@example.com", "user2@example.com"]
  }'

Remove from list

curl -X DELETE "https://api.brevo.com/v3/contacts/lists/12/contacts/remove" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "emails": ["user@example.com"]
  }'

Unsubscribe a contact

curl -X PUT "https://api.brevo.com/v3/contacts/user@example.com" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "emailBlacklisted": true
  }'

SMS marketing

Brevo sends SMS messages globally through their SMS API.

Send an SMS

curl -X POST "https://api.brevo.com/v3/transactionalSMS/sms" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "sender": "YourApp",
    "recipient": "+15551234567",
    "content": "Your verification code is: 123456",
    "type": "transactional"
  }'

Send marketing SMS

curl -X POST "https://api.brevo.com/v3/transactionalSMS/sms" \
  -H "api-key: your-api-key" \
  -H "content-type: application/json" \
  -d '{
    "sender": "YourBrand",
    "recipient": "+15551234567",
    "content": "Flash sale! 50% off today only. Reply STOP to unsubscribe.",
    "type": "marketing"
  }'

Get SMS statistics

curl -X GET "https://api.brevo.com/v3/transactionalSMS/statistics?startDate=2026-03-01&endDate=2026-03-31" \
  -H "api-key: your-api-key"

Webhooks for tracking

Webhooks notify your app about email events: delivered, opened, clicked, bounced, unsubscribed.

Configure webhooks

In Brevo dashboard: Settings → Webhooks → Add webhook

Events to track:

delivered - Email reached the inbox
opened - Recipient opened the email
clicked - Recipient clicked a link
bounced - Email bounced (hard or soft)
spam - Marked as spam
unsubscribed - Recipient unsubscribed

Handle webhook payload

app.post('/webhooks/brevo', (req, res) => {
  const event = req.body
  
  switch (event.event) {
    case 'delivered':
      console.log(`Email ${event.messageId} delivered to ${event.email}`)
      break
    case 'opened':
      console.log(`Email opened by ${event.email} at ${event.date}`)
      break
    case 'bounced':
      console.log(`Bounce: ${event.email} - ${event.reason}`)
      // Mark contact as invalid
      markContactBounced(event.email)
      break
    case 'spam':
      console.log(`Spam complaint from ${event.email}`)
      // Remove from all lists
      removeFromAllLists(event.email)
      break
    case 'unsubscribed':
      console.log(`Unsubscribed: ${event.email}`)
      break
  }
  
  res.status(200).send('OK')
})

Testing with Apidog

Email APIs have complex failure modes. You need to test templates, bounces, and webhooks. Apidog helps.

1. Mock email sending

During development, don’t send real emails. Mock the response:

pm.test('Email API accepts valid payload', () => {
  const response = pm.response.json()
  pm.expect(response).to.have.property('messageId')
  pm.expect(response.messageId).to.match(/<.*@relay\.brevo\.com>/)
})

2. Test webhook handling

Create mock webhook payloads in Apidog:

{
  "event": "bounced",
  "email": "invalid@example.com",
  "messageId": "<12345@relay.brevo.com>",
  "reason": "hard_bounce",
  "date": "2026-03-24T12:00:00Z",
  "subject": "Welcome to Our Platform"
}

Send to your webhook endpoint and verify your code handles it.

3. Validate templates

Store template payloads and test that variables are replaced correctly:

pm.test('Template variables are valid', () => {
  const payload = pm.request.body.toJSON()
  pm.expect(payload.params).to.have.property('name')
  pm.expect(payload.params).to.have.property('order_number')
})

4. Environment separation

# Development
BREVO_API_KEY: xkeysib-dev-xxx
BREVO_SENDER: dev@yourapp.com

# Production
BREVO_API_KEY: xkeysib-prod-xxx
BREVO_SENDER: noreply@yourapp.com

Test Brevo email APIs with Apidog - free

Common errors and fixes

400 Bad Request - Missing required field

Cause: Payload missing required fields.

Fix: Check the error message for specifics:

{
  "code": "invalid_parameter",
  "message": "sender.email is required"
}

401 Unauthorized

Cause: Invalid or missing API key.

Fix: Verify the api-key header is set correctly. Check the key hasn’t been revoked.

402 Payment Required

Cause: Account has exceeded limits or missing credits.

Fix:

For email: Check your plan’s email limits
For SMS: Purchase SMS credits

429 Too Many Requests

Cause: Rate limit exceeded.

Fix: Implement exponential backoff:

async function sendWithRetry(email, retries = 3) {
  for (let i = 0; i < retries; i++) {
    const response = await sendEmail(email)
    if (response.status === 429) {
      await sleep(Math.pow(2, i) * 1000)
    } else {
      return response
    }
  }
  throw new Error('Rate limit exceeded')
}

404 Contact not found

Cause: Trying to update a contact that doesn’t exist.

Fix: Use updateEnabled: true when creating contacts:

{
  "email": "new@example.com",
  "updateEnabled": true
}

This creates or updates the contact.

Alternatives and comparisons

Feature	Brevo	SendGrid	Mailchimp	Postmark
Pricing	300 emails/day free	100 emails/day free	500 emails/month free	100 emails/month free
Marketing emails	Yes	Yes	Yes	No
Transactional emails	Yes	Yes	Limited	Yes (specialized)
SMS	Yes	No	No	No
Automation	Yes	Yes	Yes	Limited
Template editor	Visual + code	Code	Visual	Code

Brevo stands out for combined email and SMS support at competitive prices.

Real-world use cases

E-commerce order flow. An online store uses Brevo for: order confirmation (transactional), shipping notification (transactional), abandoned cart recovery (marketing automation), and weekly promotions (marketing campaigns). All from one integration.

SaaS onboarding. A project management tool sends welcome emails, password resets, and team invitations via transactional API. Marketing emails announce new features to opted-in users.

SMS verification. A fintech app uses Brevo’s SMS API for two-factor authentication codes. The transactional SMS endpoint delivers codes within seconds, and webhooks track delivery failures for retry logic.

Conclusion

Here’s what you’ve learned:

Brevo APIs handle marketing, transactional email, and SMS
Authenticate with the api-key header
Use templates for consistent, maintainable emails
Manage contacts and lists for targeted campaigns
Webhooks track delivery, opens, clicks, and bounces
Test with Apidog before sending to real users

Your next steps:

Create a Brevo account and get an API key
Send your first transactional email
Create a template in the visual editor
Set up webhook handlers for bounces and unsubscribes
Test with Apidog in development

Test Brevo email APIs with Apidog - free

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FAQ

What’s the difference between Brevo and Sendinblue?Same product, new name. Sendinblue rebranded to Brevo in 2023. APIs still use api.brevo.com but you’ll see Sendinblue references in older documentation.

How many emails can I send for free?300 emails per day on the free plan. That’s 9,000 emails per month. For more, upgrade to a paid plan starting at $25/month for 20,000 emails.

Can I use Brevo for cold emails?Technically yes, but it’s risky. Cold emails have high bounce and spam rates. Brevo monitors sender reputation. High complaint rates get accounts suspended. Warm up your domain first and follow email best practices.

How do I handle email bounces?Listen for bounced webhooks. Hard bounces (invalid email) should remove contacts permanently. Soft bounces (mailbox full, temporary issues) can be retried. Track bounce rate - if it exceeds 5%, your sender reputation drops.

What’s the difference between marketing and transactional emails?Transactional emails are triggered by user actions (purchases, signups) and go to one recipient. Marketing emails are campaigns sent to many recipients simultaneously. Brevo separates them for deliverability and compliance reasons.

How do I add an unsubscribe link?Brevo automatically adds unsubscribe links to marketing emails. For transactional emails, add your own link:

<a href="{{ unsubscribe_url }}">Unsubscribe</a>

Can I send emails from my own domain?Yes. Set up SPF, DKIM, and DMARC records. Brevo provides the values in Settings → Sender & IP. Without proper authentication, emails may land in spam.

How do I schedule emails in a specific timezone?Use the scheduledAt parameter with an ISO 8601 timestamp:

{
  "scheduledAt": "2026-03-25T09:00:00-05:00"
}

What happens if I hit the rate limit?You get a 429 error. The response includes X-RateLimit-Reset header with seconds until reset. Implement exponential backoff or queue emails for later.