Mixpanel Integration

Send Featureflow flag exposures to Mixpanel as $experiment_started events, and Mixpanel's Experiments report analyses your A/B test — with Featureflow deciding who is in which arm. See A/B testing with your analytics tool for the whole loop.

Setup

Mixpanel's Experiments report reads a $experiment_started event with two string properties, Experiment name and Variant name. The JavaScript SDK's exposureIntegration sends one per user, flag and variant:

import Featureflow, { exposureIntegration } from 'featureflow-client';
import mixpanel from 'mixpanel-browser';

mixpanel.init('YOUR-MIXPANEL-PROJECT-TOKEN');

const featureflow = await Featureflow.init('your-js-client-key', {
  integrations: [
    exposureIntegration(({ key, variant }) => {
      mixpanel.track('$experiment_started', {
        'Experiment name': key,
        'Variant name': variant
      });
    })
  ]
});

Every evaluate(key) call then sends the exposure through your Mixpanel instance, so it carries your Mixpanel distinct id — no user-id mapping needed. Exposures are deduplicated per user, flag and variant for the page's lifetime, so calling evaluate() on every render will not inflate your Mixpanel event volume.

Segment every report by variant

To slice any Mixpanel report by variant, not just the Experiments report, also set a user profile property:

exposureIntegration(({ key, variant }) => {
  mixpanel.track('$experiment_started', { 'Experiment name': key, 'Variant name': variant });
  mixpanel.people.set({ [`featureflow_${key}`]: variant });
})

Send only the flags you're experimenting with

Most flags are operational and every exposure is billed Mixpanel event volume. Limit exposures to the flags you analyse:

exposureIntegration(send, { flags: ['checkout-v2', 'pricing-test'] })
// or a naming convention
exposureIntegration(send, { flags: (key) => key.startsWith('exp-') })

In Mixpanel

1. Open Experiments (under Reports) and pick the experiment named after your flag key; the variants are your Featureflow variant keys.
2. Choose the metric to compare — a conversion event you already track.

If you would rather use a different event or property name, Mixpanel lets you change what the Experiments report recognises under Settings → Project → Experimentation; the recipe above uses the defaults.

Notes

• Experiment name and Variant name must be strings — Featureflow flag keys and variant keys already are.
• Available from featureflow-client 2.6.0 / react-featureflow-client 2.6.0. On older versions, listen to the raw EVALUATION event and dedupe yourself.
• Server-side, the Node SDK emits a raw evaluation event you can forward to Mixpanel's HTTP API with your own distinct id — see the Node SDK README.

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Any problems? Reach us via the in-app chat or at support@featureflow.io.