A/B Test Pricing

METER_SLUG_A=markup-20pct       # 20% markup meter
METER_SLUG_B=flat-fee           # flat fee meter

import { Lava } from '@lavapayments/nodejs';

const lava = new Lava();

function getMeterSlug(userId: string): string {
  // Simple 50/50 split based on user ID hash
  const hash = userId.split('').reduce((a, c) => a + c.charCodeAt(0), 0);
  return hash % 2 === 0
    ? process.env.METER_SLUG_A!
    : process.env.METER_SLUG_B!;
}

app.post('/api/chat', async (req, res) => {
  const meterSlug = getMeterSlug(req.user.id);

  const forwardToken = lava.generateForwardToken({
    customer_id: req.user.customerId,
    meter_slug: meterSlug,
  });

  const response = await fetch(
    lava.providers.openai + '/chat/completions',
    {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${forwardToken}`,
        'Content-Type': 'application/json',
        'X-Lava-Metadata-Cohort': meterSlug === process.env.METER_SLUG_A! ? 'A' : 'B',
      },
      body: JSON.stringify(req.body),
    }
  );

  // stream or return response...
});

async function compareCohorts() {
  const start = new Date();
  start.setDate(start.getDate() - 7);

  const [cohortA, cohortB] = await Promise.all([
    lava.usage.retrieve({
      start: start.toISOString(),
      metadata_filters: { cohort: 'A' },
    }),
    lava.usage.retrieve({
      start: start.toISOString(),
      metadata_filters: { cohort: 'B' },
    }),
  ]);

  return {
    A: {
      requests: cohortA.totals.total_requests,
      totalCharge: parseFloat(cohortA.totals.total_charge).toFixed(2),
    },
    B: {
      requests: cohortB.totals.total_requests,
      totalCharge: parseFloat(cohortB.totals.total_charge).toFixed(2),
    },
  };
}