Build customer-facing analytics

This guide shows how to build a customer-facing analytics feature where each user sees their own personalized stats. We'll track button clicks per user and query personalized counts from a PostHog endpoint.

Step 1: Create an endpoint with a user variable

Open the SQL editor and write this query:

SELECT count() as click_count
FROM events
WHERE event = 'hedgehog_clicked'
  AND properties.user_id = {variables.user_id}

In the Variables tab, add a variable named user_id with type String.

Create the endpoint with the name hedgehog_clicks_by_user.

Step 2: Track events with user context

When tracking events, include a user_id property to associate them with specific users:

posthog.capture("hedgehog_clicked", {
  user_id: currentUser.id,
});

Step 3: Query the endpoint from your backend

Create an API route that queries the endpoint with the user's ID:

// Example: Next.js API route
export async function POST(request: Request) {
  const { user_id } = await request.json();

  const response = await fetch(
    `https://us.posthog.com/api/projects/${PROJECT_ID}/endpoints/hedgehog_clicks_by_user/run`,
    {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Authorization: `Bearer ${process.env.POSTHOG_API_KEY}`,
      },
      body: JSON.stringify({
        variables: { user_id },
      }),
    }
  );

  const data = await response.json();
  return Response.json({ click_count: data.results?.[0]?.[0] ?? 0 });
}

Then fetch from your frontend:

const response = await fetch("/api/hedgehog-clicks", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ user_id: currentUser.id }),
});

const { click_count } = await response.json();

Security considerations

1. Never expose API keys client-side - Always proxy through your backend
2. Variables are required - Endpoints with variables require values, preventing accidental data leaks
3. Validate user IDs - In production, verify the user is authorized to query data for the requested user_id

Next steps

• Materialize your endpoint for faster response times
• Generate a typed SDK for type-safe API calls
• Learn about caching to reduce costs