I am currently using GA4 + Growthbook + NextJS, however I am using Growthbook server side so I can use the middleware to A/B test pages and redirect users to the page they need to view. I need to send the "experiment_viewed" event to Google Analytics for it to show in Growthbook what would be the best way to do this? Currently have this code snippet in the trackingCallback but it is not submitting events to GA4

const gb = new GrowthBook({
    apiHost: process.env.NEXT_PUBLIC_GROWTHBOOK_API_HOST,
    clientKey: process.env.NEXT_PUBLIC_GROWTHBOOK_CLIENT_KEY,
    enableDevMode: true,
    trackingCallback: async (experiment, result) => {
      console.log('Tracking event:', experiment.key, result.variationId || result.key)

      // Server-side GA4 tracking for experiments
      try {
        // Construct GA payload with proper parameter structure for GA4
        const payload = {
          client_id: clientId,
          user_id: userId, // Including user ID for cross-device tracking
          user_properties: {
            gb_user_id: { value: userId },
          },
          events: [
            {
              name: 'experiment_view', // GA4 typically uses snake_case
              params: {
                experiment_id: experiment.key,
                variation_id: result.variationId || result.key,
                experiment_name: experiment.name || experiment.key,
              },
            },
          ],
        }

        // GA4 Measurement Protocol endpoint
        const endpoint = `<https://www.google-analytics.com/mp/collect?measurement_id=${process.env.GA_MEASUREMENT_ID}&api_secret=${process.env.GA_API_SECRET}>`

        // Send event to Google Analytics with better error reporting
        const response = await fetch(endpoint, {
          method: 'POST',
          body: JSON.stringify(payload),
          headers: {
            'Content-Type': 'application/json',
          },
        })

        if (!response.ok) {
          const errorText = await response.text()
          console.error('GA4 API error:', response.status, errorText)
        } else {
          console.log('GA4 event sent successfully')
        }
      } catch (error) {
        console.error('Error sending GA event:', error)
      }
    },
  })

It is logging "GA4 Event is sent successfully, but it is not showing up

How long has it been?

A few days

huh

Also been looking on the RealTime view in Google Analytics still nothing unfortunately

looks like the code is executing correctly - but perhaps that endpoint is failing?

When logging the response I get a 204 status code

huh

No nothing there, also queried in BigQuery for it, but I didn't find it

can you just use curl or postman or something to send an event and see if you can see it in GA4?

The response I am getting:

{
  "validationMessages": []
}

does that event show up in GA4?