Example of using analytics + a plugin (or listener) to send campaign data to a backend serverless function

app-code.js

import Analytics from 'analytics'

// Listen for ?utm params and send data to Netlify function
const customUtmTokenPlugin = {
  NAMESPACE: 'save-campaign-data',
  campaign: ({ payload }) => {
    const { campaign } = payload
    console.log('utm data', campaign)
    fetch('/.netlify/functions/save-campaign-data', {
      method: 'POST',
      headers: new Headers({
        'Content-Type': 'application/json'
      }),
      body: JSON.stringify(campaign)
    })
  }
}

const analytics = Analytics({
  app: 'app-name',
  plugins: [
    customUtmTokenPlugin,
    // ... other plugins
  ]
})

// OR with a listener
analytics.on('campaign', ({ payload }) => {
  fetch('/.netlify/functions/save-campaign-data', {
    method: 'POST',
    headers: new Headers({
      'Content-Type': 'application/json'
    }),
    body: JSON.stringify(payload)
  })
})

save-campaign-data.js

// Netlify Lambda function
module.exports = async (event, context) => {
  const campaignInfo = JSON.parse(event.body)

  // Save to your DB of choice

  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'campaign data saved successfully',
    }),
  }
}