Segment proxy (Node)

segment-proxy-node.ts

import express from 'express';
import Segment from 'analytics-node';

const instance = new Segment('YOUR_WRITE_KEY');

const port = 3000;
const app = express();

// Enables JSON parsing middleware
app.use(express.json())

// Registers the new endpoint which will handle the Segment events
app.post('/analytics/segment/v1/batch', (req, res) => {
  const { batch } = req.body;

  const results = batch.map((event) => {
    /**
     * It is important to remove the `messageId` from the event
     * when you need to send the same event to multiple destinations.
     *
     * Otherwise, Segment will only process the first event with
     * a given `messageId`.
     */
    delete event.messageId;

    /**
     * Here you can alter the different payload properties
     * (context, traits, properties, etc.) to standardize your events.
     *
     * You could also implement a custom caching layer to prevent sending
     * duplicate events for destinations such as Braze.
     */
    event.context = {
      ...event.context,
      yourStandardProperty: "a standard value",
    };

    event.traits = {
      ...event.traits,
      yourOtherStandardProperty: "another standard value",
    };

    /**
     * You could send the "same" event
     * more than once, to different destinations,
     * with adapted payloads.
     */
    event.integrations = {
      ...event.integrations,
      Braze: false,
    };

    /**
     * You can reject (skip) events
     * for any arbitraty reasons.
     */
    if (event.type === "identify") {
      instance.identify(event);

      return "handled";
    }

    return "skipped";
  });
  
  res.status(200).send(results);
});

app.listen(port, () => console.log(`Server listening at http://localhost:${port}`));